Patent Publication Number: US-2022238604-A1

Title: Photoelectric conversion devices

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0011033, filed on Jan. 26, 2021 in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference in its entirety herein. 
     1. TECHNICAL FIELD 
     The present inventive concepts relate to a photoelectric conversion device, and more particularly, to a photoelectric conversion device for detecting light with a particular wavelength band. 
     2. DISCUSSION OF RELATED ART 
     A photoelectric conversion device detects light by converting light into electrical energy. Photoelectric conversion devices have increasingly varied applications, such as security, facial recognition, autonomous driving, virtual reality (VR), and augmented reality (AR). Therefore, there is an increasing demand for developing a photoelectric conversion device for detecting light of various specific wavelength bands. In general, a photoelectric conversion layer for converting light into electrical energy in the photoelectric conversion device is composed of silicon. However, a detectable wavelength band is limited and the photoelectric conversion layer has an indirect bandgap which leads to a decrease in light conversion efficiency. 
     SUMMARY 
     The present inventive concepts provide a photoelectric conversion device that detects light of a specific wavelength band with increased light conversion efficiency. 
     Accordingly, embodiments of the present inventive concepts provide the following photoelectric conversion devices. 
     According to an embodiment of the present inventive concepts, a photoelectric conversion device includes a substrate and a wiring layer disposed on the substrate. The wiring layer includes a wiring structure and a wiring insulating layer that surrounds the wiring structure. A reflective layer is disposed on the wiring layer. The reflective layer is electrically connected to the wiring structure. A semi-permeable metal layer is spaced apart from the reflective layer in a thickness direction of the substrate. The semi-permeable metal layer faces the reflective layer to form a microcavity between the reflective layer and the semi-permeable metal layer. A stacked structure is between the reflective layer and the semi-permeable metal layer in the thickness direction of the substrate. The stacked structure includes a photoelectric conversion layer, a transparent electrode layer, and an insulating optical spacer. 
     According to an embodiment of the present inventive concepts, a photoelectric conversion device includes a substrate comprising a plurality of pixel regions. A wiring layer is disposed on the substrate. The wiring layer includes a wiring structure and a wiring insulating layer that surrounds the wiring structure. A plurality of reflective layers is disposed on the wiring layer. The plurality of reflective layers is electrically connected to the wiring structure and corresponds to the plurality of pixel regions, respectively. Each reflective layer of the plurality of reflective layers functions as a lower electrode. A photoelectric conversion layer is disposed on the plurality of reflective layers and extends over the plurality of pixel regions. A transparent electrode layer covers the photoelectric conversion layer and functions as an upper electrode. An insulating optical spacer covers the transparent electrode layer. A semi-permeable metal layer is spaced apart from the plurality of reflective layers in a thickness direction of the substrate. The semi-permeable metal layer faces the plurality of reflective layers to form a plurality of microcavities therebetween. The semi-permeable metal layer covers the insulating optical spacer over the plurality of pixel regions. A passivation layer covers the semi-permeable metal layer. A plurality of microlenses is disposed on the passivation layer and corresponds to the plurality of pixel regions, respectively. 
     According to an embodiment of the present inventive concepts, a photoelectric conversion device includes a substrate having a plurality of pixel regions. A wiring layer is disposed on the substrate and includes a wiring structure and a wiring insulating layer that surrounds the wiring structure. A plurality of reflective layers is disposed on the wiring layer. The plurality of reflective layers corresponds to the plurality of pixel regions, respectively. Each of the plurality of reflective layers functions as a lower electrode and has a first thickness. The plurality of reflective layers is electrically connected to the wiring structure. A photoelectric conversion layer extends over the plurality of pixel regions and has a second thickness. The photoelectric conversion layer includes at least one material selected from organic photoelectric material, quantum dot material, organic perovskite material, and inorganic perovskite material. A transparent electrode layer covers the photoelectric conversion layer and functions as an upper electrode. The transparent electrode layer has a third thickness that is less than the first thickness. An insulating optical spacer covers the transparent electrode layer and has a fourth thickness that is greater than the second thickness. A semi-permeable metal layer is over the plurality of pixel regions and covers the insulating optical spacer. The semi-permeable metal layer faces the plurality of reflective layers and is spaced apart from the plurality of reflective layers in a thickness direction of the substrate to form a plurality of microcavities. The semi-permeable metal layer has a fifth thickness that is less than the first thickness. A passivation layer covers the semi-permeable metal layer. A plurality of microlenses is disposed on the passivation layer and corresponds to the plurality of pixel regions, respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts; 
         FIG. 2A  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts; 
         FIG. 2B  is a plan view illustrating some of components of the photoelectric conversion device of  FIG. 2A  according to an embodiment of the present inventive concepts; 
         FIG. 3A  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts; 
         FIG. 3B  is a plan view illustrating some components of the photoelectric conversion device of  FIG. 3A  according to an embodiment of the present inventive concepts; 
         FIG. 4A  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts; 
         FIG. 4B  is a plan view illustrating some of components of the photoelectric conversion device of  FIG. 4A  according to an embodiment of the present inventive concepts; 
         FIG. 5  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concept; 
         FIGS. 6A and 6B  are cross-sectional views illustrating main parts of a photoelectric conversion device according to embodiments of the present inventive concepts; 
         FIGS. 7A and 7B  are cross-sectional views illustrating main parts of a photoelectric conversion device according to embodiments of the present inventive concepts; 
         FIG. 8  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts; 
         FIGS. 9A, 9B, 10A, 10B, 11, 12A, and 12B  are cross-sectional views illustrating a method of manufacturing a photoelectric conversion device according to embodiments of the present inventive concepts; 
         FIG. 13  is a block diagram illustrating a configuration of a photoelectric conversion device according to an embodiment of the present inventive concepts; 
         FIG. 14  is a block diagram illustrating a configuration of a photoelectric conversion device according to an embodiment of the present inventive concepts; and 
         FIG. 15  is a lead-out circuit diagram of a photoelectric conversion device according to an embodiment of the present inventive concepts. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts. 
     Referring to  FIG. 1 , a photoelectric conversion device  1  may include a substrate  100 , a wiring layer  200 , a plurality of reflective layers  310 , a photoelectric conversion layer  320 , a transparent electrode layer  330 , an insulating optical spacer  340 , and a semi-permeable metal layer  350 . The photoelectric conversion device  1  may include a plurality of pixel regions in which a plurality of pixels are disposed. For example, the photoelectric conversion device  1  may include a first pixel region PX 1  and a second pixel region PX 2 . 
     In an embodiment, the substrate  100  may include, for example, any one of a bulk semiconductor substrate, an epitaxial semiconductor substrate, or a silicon on insulator (SOI) substrate. The substrate  100  may include, for example, silicon (Si). However, embodiments of the present inventive concepts are not limited thereto. For example, the substrate  100  may include a semiconductor element such as germanium (Ge), or a compound semiconductor such as silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs), and indium phosphide (InP). In some embodiments, the substrate  100  may include a semiconductor substrate having a first conductivity type. For example, the substrate  100  may include a p-type silicon substrate. In some embodiments, the substrate  100  may include a p-type bulk substrate and a p-type or n-type epitaxial layer grown thereon. In some embodiments, the substrate  100  may include an n-type bulk substrate and the p-type or n-type epitaxial layer grown thereon. In some embodiments, the substrate  100  may include an organic plastic substrate. 
     A device isolation film  110  for defining an active region may be formed in the substrate  100 . An impurity region  120  may be formed in a portion of the active region. In some embodiments, the impurity region  120  may be a contact region to which a wiring via  220  is connected. However, embodiments of the present inventive concepts are not limited thereto. For example, in some embodiments, the impurity region  120  may be a floating diffusion region. A plurality of gate electrodes constituting a portion of a plurality of transistors TR may be formed on the substrate  100 . For example, the plurality of transistors TR may include a transmission transistor that is configured to transmit charges generated in the photoelectric conversion layer  320  to the floating diffusion region, a reset transistor that is configured to periodically reset the charges stored in the floating diffusion region, a drive transistor that acts as a source follower buffer amplifier and is configured to buffer a signal according to the charges stored in the floating diffusion region, and a selection transistor that acts as switching and addressing element for selecting at least one of the plurality of pixels. However, embodiments of the present inventive concepts are not limited thereto and the plurality of transistors TR may vary. 
     The wiring layer  200  may be formed on the substrate  100 . The wiring layer  200  may include a plurality of wiring patterns  210 , a plurality of wiring vias  220 , and a wiring insulating layer  230 . In an embodiment, the plurality of wiring patterns  210  and the plurality of wiring vias  220  may include, for example, at least one compound selected from tungsten, aluminum, copper, tungsten silicide, titanium silicide, tungsten nitride, titanium nitride, doped polysilicon, and the like. However, embodiments of the present inventive concepts are not limited thereto. 
     A stacked structure of the plurality of wiring patterns  210  and the plurality of wiring vias  220  may be referred to as a wiring structure MS. The wiring structure MS may be electrically connected to the active region of the substrate  100 . For example, as shown in the embodiment of  FIG. 1 , a lower surface of the wiring via  220  may directly contact the impurity region  120  for electrical connection to the active region of the substrate  100 . The plurality of wiring vias  220  may electrically connect some of the plurality of wiring patterns  210  located at different vertical levels to each other, or may electrically connect between some of the plurality of wiring patterns  210  and the active region of the substrate  100 , or may electrically connect between some of the plurality of wiring patterns  210  and at least one of the plurality of reflective layers  310 . 
     In some embodiments, at least one of the plurality of wiring patterns  210  and at least one of the plurality of wiring vias  220  may be formed together to form an integrated body. In some embodiments, each of the plurality of wiring patterns  210  and the plurality of wiring vias  220  may have a tapered shape having a width that narrows in a horizontal direction from an upper side to a lower side thereof. That is, the plurality of wiring patterns  210  and the plurality of wiring vias  220  may be wider in a horizontal direction away from the substrate  100 . For example, in an embodiment, the plurality of wiring patterns  210  may have a thickness in a range of about 750 μm to about 2,000 μm. In some embodiments, among the plurality of wiring patterns  210 , the farthest wiring pattern of the plurality of wiring patterns  210  from the substrate  100  may have the largest thickness, and the closest wiring pattern of the plurality of wiring patterns  210  to the substrate  100  may have the smallest thickness. For example, as shown in the embodiment of  FIG. 1 , the wiring via  220  immediately adjacent to the reflective layer  310  may have a larger width than the wiring via  220  immediately adjacent to the impurity region  120 . 
     The wiring insulating layer  230  may be arranged to wrap (e.g., surround) the wiring structure MS, which is the stacked structure of the plurality of wiring patterns  210  and the plurality of wiring vias  220  on the substrate  100 . In an embodiment, the wiring insulating layer  230  may include an insulating material such as silicon oxide, silicon nitride, silicon oxynitride, and the like. However, embodiments of the present inventive concepts are not limited thereto. 
     On the wiring layer  200 , the plurality of reflective layers  310  corresponding to the plurality of pixel regions PX 1  and PX 2 , respectively, may be formed. The plurality of reflective layers  310  may have a first thickness T 1  (e.g., length in a thickness direction of the substrate  100 ). For example, in an embodiment, the first thickness T 1  thereof may be in a range of about 1,000 Å to about 2,000 Å. 
     The plurality of reflective layers  310  may be electrically connected to the wiring structure MS. The plurality of reflective layers  310  may be electrically connected to the active region of the substrate  100  through the wiring structure MS to function as a lower electrode. The plurality of reflective layers  310  may include a material having a relatively high reflectivity. For example, in an embodiment, the reflectivity of the plurality of reflective layers  310  may be in a range of about 80% or more for light of the wavelength band to be detected by the photoelectric conversion device  1 . 
     In some embodiments, the plurality of reflective layers  310  may include metal, or conductive metal nitride. For example, in an embodiment, the plurality of reflective layers  310  may include at least one compound selected from aluminum (Al), silver (Ag), an alloy of aluminum and silver, silver-based oxide (Ag—O), an APC alloy (an alloy including Ag, Pd, and Cu), rhodium (Rh), copper (Cu), palladium (Pd), nickel (Ni), ruthenium (Ru), iridium (Ir), platinum (Pt), and titanium nitride (TiN). However, embodiments of the present inventive concepts are not limited thereto. For example, in some embodiments, the plurality of reflective layers  310  may include a multi-layer structure in which a first layer and a second layer are stacked, the first layer including metal or conductive metal nitride and the second layer including a transparent conductive material. For example, the transparent conductive material may include indium tin oxide (ITO), indium zinc oxide (IZO), ZnO, antimony-doped tin oxide (ATO), or Al-doped zinc oxide (AZO). In some embodiments, the plurality of reflective layers  310  may include a distributed Bragg Reflector (DBR). For example, the plurality of reflective layers  310  may include a plurality of layers in which a low refractive index layer and a high refractive index layer each having a thickness of mλ/4n are alternately stacked. Here, λ is a wavelength of the light to be reflected, n is a refractive index of a medium, and m is an odd number. The low refractive index layer may include, for example, silicon oxide (SiO 2 , refractive index of 1.4) or aluminum oxide (Al 2 O 3 , refractive index of 1.6), and the high refractive index layer may include, for example, silicon nitride (Si 3 N 4 , refractive index of 2.05˜2.25), titanium nitride (TiO 2 , refractive index is 2 or more), or Si—H (refractive index is 3 or more). 
     The photoelectric conversion layer  320  may be formed on the plurality of reflective layers  310 . For example, the photoelectric conversion layer  320  may be formed directly on an upper surface of the plurality of reflective layers  310  (e.g., in a thickness direction of the substrate  100 ). The photoelectric conversion layer  320  may extend in a horizontal direction and cover the plurality of reflective layers  310  over the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 . That is, portions of the photoelectric conversion layer  320  disposed in each of the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 , may constitute the plurality of pixels. The photoelectric conversion layer  320  may have a second thickness T 2  (e.g., length in a thickness direction of the substrate  100 ). For example, in an embodiment, the photoelectric conversion layer  320  may include at least one material selected from an organic photoelectric material, quantum dot material, organic perovskite material, and inorganic perovskite material. However, embodiments of the present inventive concepts are not limited thereto. The photoelectric conversion layer  320  may be formed through a deposition method, a coating method, or a printing method. For example, the organic photoelectric material may be bay-annulated indigo (BAI), the quantum dot material may be PbS, or InAs, and the perovskite material may be MAPbX 3  (CH 3 NH 3 PbX 3 ). However, embodiments of the present inventive concepts are not limited thereto. The photoelectric conversion layer  320  may include at least one material selected from the organic photoelectric material, the quantum dot material, the organic perovskite material, and the inorganic perovskite material that absorbs the light of the wavelength band to be detected by the photoelectric conversion device  1  to cause photoelectric conversion. 
     In some embodiments, the photoelectric conversion layer  320  may have a stacked structure that may include a base photoelectric conversion layer including at least one material selected from the organic photoelectric material, the quantum dot material, the organic perovskite material, and the inorganic perovskite material, an electron blocking layer (EBL) covering a bottom surface of the base photoelectric conversion layer, and a hole blocking layer (HBL) covering a top surface of the base photoelectric conversion layer. For example, the EBL and the HBL may include AlGaN. 
     The transparent electrode layer  330  may be formed on the photoelectric conversion layer  320 . For example, as shown in the embodiment of  FIG. 1 , the transparent electrode layer  330  may be disposed directly on the photoelectric conversion layer  320  (e.g., in a thickness direction of the substrate  100 ). The transparent electrode layer  330  may cover the photoelectric conversion layer  320  over the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 . The transparent electrode layer  330  may have a third thickness T 3  (e.g., length in a thickness direction of the substrate  100 ). In some embodiments, the third thickness T 3  may be less than each of the first thickness T 1  and the second thickness T 2 . For example, in an embodiment, the third thickness T 3  may be in a range of about 100 Å to about 300 Å. For example, in an embodiment, the transparent electrode layer  330  may include ITO, IZO, ZnO, ATO, or AZO. However, embodiments of the present inventive concepts are not limited thereto. 
     Each of the plurality of reflective layers  310 , a portion of the photoelectric conversion layer  320  and a portion of the transparent electrode layer  330  that each vertically overlap each of the plurality of reflective layers  310  may constitute a unit photoelectric device for each pixel. For example, the photoelectric conversion device  1  may include a plurality of unit photoelectric devices for the plurality of pixels. The transparent electrode layer  330  may function as an upper electrode of the plurality of unit photoelectric devices, and the plurality of reflective layers  310  may function as the lower electrode of the plurality of unit photoelectric devices. The transparent electrode layer  330  may be electrically connected to the wiring structure MS through a conductive via. 
     The insulating optical spacer  340  may be formed on the transparent electrode layer  330 . The insulating optical spacer  340  may cover the transparent electrode layer  330 . The insulating optical spacer  340  may have a fourth thickness T 4  (e.g., length in a thickness direction of the substrate  100 ). In an embodiment, the insulating optical spacer  340  may include oxide, nitride, oxynitride, or combinations thereof. However, embodiments of the present inventive concepts are not limited thereto. The photoelectric conversion layer  320 , the transparent electrode layer  330 , and the insulating optical spacers  340  may respectively include materials having similar refractive indexes. 
     A stacked structure ST including the photoelectric conversion layer  320 , the transparent electrode layer  330 , and the insulating optical spacer  340  may have a fifth thickness T 5  (e.g., length in a thickness direction of the substrate  100 ). The fifth thickness T 5  may be selected considering the wavelength band of the light to be detected by the photoelectric conversion device  1 . For example, in an embodiment, the fifth thickness T 5  may be a value that is about ¼ (λ/4) of the wavelength λ of light to be detected by the photoelectric conversion device  1  that penetrates the stacked structure ST. For example, when the light to be detected by the photoelectric conversion device  1  has a wavelength of 1,400 nm and enters the stacked structure ST in the vertical direction, assuming that the refractive index of each of the photoelectric conversion layer  320 , the electrode layer  330 , and the insulating optical spacer  340  is 1 for the convenience of calculation, the fifth thickness T 5  may be in a range of about 3,500 Å which is about ¼ of 1,400 nm. 
     Thus, the insulating optical spacer  340  may be formed to have the fourth thickness T 4 , which is a value obtained by subtracting the third thickness T 3  and the second thickness T 2  from the fifth thickness T 5 , wherein the fifth thickness T 5  is selected considering the wavelength of the light to be detected by the photoelectric conversion device  1  and the refractive index of each of the photoelectric conversion layer  320 , the transparent electrode layer  330 , and the insulating optical spacer  340 . For example, in an embodiment, the fourth thickness T 4  may have a value in a range of about 25% to about 75% of the fifth thickness T 5 . 
     In some embodiments, when the light to be detected by the photoelectric conversion device  1  has a relatively long wavelength, the insulating optical spacer  340  may be formed relatively thicker. In some embodiments, the insulating optical spacer  340  may be formed thicker than the photoelectric conversion layer  320 . For example, the fourth thickness T 4  may be greater than the second thickness T 2 . In some embodiments, the second thickness T 2  may be in a range of about 500 Å to about 1,000 Å, and the fourth thickness T 4  may be in a range of about 1,500 Å or more. However, embodiments of the present inventive concepts are not limited thereto. 
     A semi-permeable metal layer  350  may be formed on the insulating optical spacer  340 . For example, as shown in the embodiment of  FIG. 1 , the semi-permeable metal layer  350  may be disposed directly on an upper surface of the insulating optical spacer  340  (e.g., in a thickness direction of the substrate  100 ). The semi-permeable metal layer  350  may cover the insulating optical spacer  340  over the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 . The semi-permeable metal layer  350  may have a sixth thickness T 6  (e.g., length in a thickness direction of the substrate  100 ). As shown in the embodiment of  FIG. 1 , the sixth thickness T 6  may be less than the first thickness T 1 . In some embodiments, the sixth thickness T 6  may be greater than the third thickness T 3 . For example, the sixth thickness T 6  may be in a range of about 200 Å to about 400 Å. However, embodiments of the present inventive concepts are not limited thereto. 
     The semi-permeable metal layer  350  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  1 . For example, in an embodiment, a light transmittance of the semi-permeable metal layer  350  may be in a range of about 30% to about 70% for the light of the wavelength band to be detected by the photoelectric conversion device  1 . Therefore, a reflectivity of the semi-permeable metal layer  350  may be in a range of about 70% to 30% for the light of the wavelength band to be detected by the photoelectric conversion device  1 . The reflectivity of the semi-permeable metal layer  350  may be less than the reflectivity of the plurality of reflective layers  310 . 
     In an embodiment, the semi-permeable metal layer  350  may include metal material formed to have a relatively thin thickness and to be semi-permeable for the light of the wavelength band to be detected by the photoelectric conversion device  1 . For example, the semi-permeable metal layer  350  may include metal, or conductive metal nitride. For example, the semi-permeable metal layer  350  may include at least one compound selected from aluminum (Al), silver (Ag), an alloy of aluminum and silver, silver-based oxide (Ag—O), an APC alloy (an alloy including Ag, Pd, and Cu), rhodium (Rh), copper (Cu), palladium (Pd), nickel (Ni), ruthenium (Ru), iridium (Ir), platinum (Pt), and titanium nitride (TiN). 
     Each of the plurality of reflective layers  310  and a corresponding portion of the semi-permeable metal layer  350  overlapping with each other in the vertical direction may be spaced apart from each other (e.g., in a direction parallel to a thickness direction of the substrate  100 ) to form a microcavity. The photoelectric conversion device  1  may include a plurality of microcavities that are formed by the plurality of reflective layers  310  and the semi-permeable metal layer  350 , corresponding to the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 . 
     The photoelectric conversion device  1  may further include a passivation layer  360  and a plurality of microlenses  370 . 
     The passivation layer  360  may be formed on the semi-permeable metal layer  350 . For example, as shown in the embodiment of  FIG. 1 , a lower surface of the passivation layer  360  may be disposed directly on an upper surface of the semi-permeable metal layer  350  (e.g., in a thickness direction of the substrate  100 ). The passivation layer  360  may cover the semi-permeable metal layer  350 . In an embodiment, the passivation layer  360  may include, for example, oxide, nitride, oxynitride, or combinations thereof. In some embodiments, the passivation layer  360  may include a stacked structure of hafnium oxide, silicon nitride, and hafnium oxide. However, embodiments of the present inventive concepts are not limited thereto. 
     The plurality of microlenses  370  may be disposed on the passivation layer  360 . For example, as shown in the embodiment of  FIG. 1 , a lower surface of the plurality of microlenses  370  may be disposed directly on an upper surface of the passivation layer  360  (e.g., in a thickness direction of the substrate  100 ). In some embodiments, the plurality of microlenses  370  may be disposed on the passivation layer  360  in a matrix array or a honeycomb array. In an embodiment, the plurality of microlenses  370  may be arranged to correspond to the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 , respectively. However, embodiments of the present inventive concepts are not limited thereto. Each of the plurality of microlenses  370  may concentrate the light incident on the photoelectric conversion device  1  to each of the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 . In some embodiments, the microlens  370  may include an organic layer  372  and an inorganic layer  374  that conformally covers the surface of the organic layer  372 . For example, in an embodiment, the organic layer  372  may include a TMR-based resin (available from Tokyo Ohka Kogyo, Co.), or an MFR-based resin (available from Japan Synthetic Rubber Corporation). However, embodiments of the present inventive concepts are not limited thereto. 
     Light L 2  which is a portion of light L 1  incident on the photoelectric conversion device  1  through the microlens  370  may be reflected on the semi-permeable metal layer  350  and released to the outside of the photoelectric conversion device  1 , and light L 3  which is a remaining portion of light L 1  may pass through the semi-permeable metal layer  350  and enter the stacked structure ST. The light L 3  incident into the stacked structure ST may be repeatedly reflected between the reflective layer  310  and the semi-permeable metal layer  350 , and light L 4  which is a portion of the light L 3  may pass through the semi-permeable metal layer  350  to be released to the outside while a remaining portion of the light L 3  is reflected back towards the reflective layer. 
     In the photoelectric conversion device  1  according to an embodiment of the present inventive concepts, the plurality of reflective layers  310  and the semi-permeable metal layer  350  may constitute the plurality of microcavities that repeatedly reflect the light L 3  incident into the stacked structure ST, and thus, light conversion efficiency may be increased. 
     In the photoelectric conversion device  1  according to an embodiment of the present inventive concepts, the photoelectric conversion layer  320  may be formed separately from the substrate  100 , and thus, when the photoelectric conversion layer  320  is formed to include at least one material selected from the organic photoelectric material, the quantum dot material, and the organic or inorganic perovskite material that are suitable for the light of the wavelength band to be detected by the photoelectric conversion device  1 , light of various wavelength bands may be detected. 
     In the photoelectric conversion device  1  according to an embodiment of the present inventive concepts, the stacked structure ST formed by the photoelectric conversion layer  320 , the transparent electrode layer  330 , and the insulating optical spacer  340  may be arranged between the plurality of reflective layers  310  and the semi-permeable metal layer  350  that constitute the plurality of microcavities, so that even when detecting light of a relatively long wavelength band, the photoelectric conversion layer  320  may be made thinner and thus, the manufacturing cost and the ease of process may be increased. 
     In addition, in the photoelectric conversion device  1  according to an embodiment of the present inventive concepts, the plurality of reflective layers  310  may function as the lower electrode and the transparent electrode layer  330  formed at a relatively small separation distance corresponding to the second thickness T 2  from the reflective layers  310  may function as the upper electrode, instead of the semi-permeable metal layer  350  formed at a relatively large separation distance corresponding to the fifth thickness T 5 , and thus, electrical characteristics may be increased and light conversion efficiency may be increased. 
       FIG. 2A  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concept, and  FIG. 2B  is a plan layout illustrating some of components of the photoelectric conversion device. In  FIGS. 2A and 2B , the same member numerals as in  FIG. 1  show the same components, and the duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to  FIGS. 2A and 2B  together, a photoelectric conversion device  1   a  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340 , and a semi-permeable metal layer  350   a . The photoelectric conversion device  1   a  may further include a passivation layer  360   a  and the plurality of microlenses  370 . 
     The semi-permeable metal layer  350   a  may be formed on the insulating optical spacer  340  (e.g., directly thereon in a thickness direction of the substrate  100 ). The semi-permeable metal layer  350   a  may cover a portion of the insulating optical spacer  340 . The semi-permeable metal layer  350   a  may have a maximum thickness of the sixth thickness T 6 . 
     The semi-permeable metal layer  350   a  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  1   a . For example, in an embodiment, a light transmittance of the semi-permeable metal layer  350   a  may be in a range of about 30% to about 70% for the light of the wavelength band to be detected by the photoelectric conversion device  1   a . The semi-permeable metal layer  350   a  may have a plurality of openings  3500 . The plurality of openings  3500  may extend from a top surface of the semi-permeable metal layer  350   a  to a bottom surface thereof. The plurality of openings  3500  may fully penetrate the semi-permeable metal layer  350   a  (e.g., in a thickness direction of the substrate  100 ), and thus, the insulating optical spacer  340  may be exposed positioned at a bottom surface of the plurality of openings  3500 . 
     In an embodiment, the plurality of openings  3500  may be in a center portion of the plurality of microlenses  370  in plan view. For example, the plurality of openings  3500  may be formed in a center portion of the plurality of microlenses in a direction parallel to an upper surface of the substrate  100 . The plurality of openings  3500  may be arranged to overlap the center portion of the plurality of microlenses  370  in the vertical direction (e.g., a direction parallel to a thickness direction of the substrate  100 ). 
     The passivation layer  360   a  may be formed on the semi-permeable metal layer  350   a  (e.g., directly thereon in a thickness direction of the substrate  100 ). The passivation layer  360   a  may fill the plurality of openings  3500  and have a plurality of extension portions  360 Ea extending toward the insulating optical spacer  340 . A lower surface of each of the plurality of extension portions  360 Ea of the passivation layer  360   a  may directly contact an upper surface of the insulating optical spacer  340 . 
     Light L 2  which is a portion of light L 1  incident on the photoelectric conversion device  1   a  through the microlens  370  may be reflected on the semi-permeable metal layer  350   a  and released to the outside of the photoelectric conversion device  1   a , and light L 3  which is a remaining portion of light L 1  may pass through the opening  3500  or penetrate the semi-permeable metal layer  350   a  and enter the stacked structure ST. The light L 3  incident into the stacked structure ST may be repeatedly reflected between the reflective layer  310  and the semi-permeable metal layer  350   a , and light L 4  which is a portion of the light L 3  may pass through the semi-permeable metal layer  350   a  to be released to the outside while the remaining portion of light L 3  is reflected back towards the reflective layer  310 . 
     In an embodiment, the light L 1  incident on the photoelectric conversion device  1   a  through the microlens  370  may be focused on the opening  3500  of the semi-permeable metal layer  350   a  vertically overlapping the center portion of the microlens  370 . Therefore, the photoelectric conversion device  1   a  may have the plurality of openings  3500  respectively corresponding to the plurality of microlenses  370 , and thus, a relatively large amount of the light L 1  incident on the photoelectric conversion device  1   a  through the microlens  370  may be incident into the stacked structure ST, thereby increasing light conversion efficiency. 
       FIG. 3A  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts, and  FIG. 3B  is a plan layout illustrating some of components of the photoelectric conversion device. In  FIGS. 3A and 3B , the same reference numerals as in  FIGS. 1 to 2B  denote the same components, and duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to  FIGS. 3A and 3B  together, a photoelectric conversion device  1   b  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340 , and a semi-permeable metal layer  350   b . The photoelectric conversion device  1   b  may further include a passivation layer  360   b  and the plurality of microlenses  370 . 
     The semi-permeable metal layer  350   b  may be formed on the insulating optical spacer  340  (e.g., directly thereon in a thickness direction of the substrate  100 ). The semi-permeable metal layer  350   b  may cover the insulating optical spacer  340 . The semi-permeable metal layer  350   b  may have the maximum thickness of the sixth thickness T 6 . 
     The semi-permeable metal layer  350   b  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  1   b . For example, in an embodiment, a light transmittance of the semi-permeable metal layer  350   b  may be in a range of about 30% to about 90% for the light of the wavelength band to be detected by the photoelectric conversion device  1   b . The semi-permeable metal layer  350   b  may have a plurality of recesses  350 R. The plurality of recesses  350 R may extend toward the bottom surface of the semi-permeable metal layer  350   b . However, the plurality of recesses  350 R may not fully penetrate the semi-permeable metal layer  350   b . Therefore, the insulating optical spacer  340  may not be exposed on the bottom surface of the plurality of recesses  350 R and a portion of the semi-permeable metal layer  350   b  may be exposed. The portion of the semi-permeable metal layer  350   b  exposed on the bottom surface of the plurality of recesses  350 R may have a relatively thin thickness. For example, the portion of the semi-permeable metal layer  350   b  exposed on the bottom surface of the plurality of recesses  350 R may have a thickness less than the sixth thickness T 6 . The portion of the semi-permeable metal layer  350   b  exposed on the bottom surface of the plurality of recesses  350 R may have a light transmittance that is greater than the light transmittance of a remaining portion of the semi-permeable metal layer  350   b.    
     In an embodiment, the plurality of recesses  350 R may be in the center portion of the plurality of microlenses  370  in a plan view (e.g., in a direction parallel to an upper surface of the substrate  100 ). The plurality of recesses  350 R may be arranged to overlap the center portion of the plurality of microlenses  370  in the vertical direction (e.g., in a direction parallel to a thickness direction of the substrate  100 ). 
     The passivation layer  360   b  may be formed on the semi-permeable metal layer  350   b  (e.g., directly thereon in a thickness direction of the substrate  100 ). The passivation layer  360   b  may fill the plurality of recesses  350 R and have a plurality of extension portions  360 Eb extending toward the insulating optical spacer  340 . Each of the plurality of extension portions  360 Eb of the passivation layer  360   b  may be spaced apart from the insulating optical spacer  340  without contacting the insulating optical spacer  340 . For example, as shown in the embodiment of  FIG. 3A , the exposed portion of the plurality of recesses  350 R may be interposed between the insulating optical spacer  340  and the plurality of extension portions  360 Eb in a thickness direction of the substrate  100 . 
     Light L 2  which is a portion of the light L 1  incident on the photoelectric conversion device  1  through the microlenses  370  may be reflected on the semi-permeable metal layer  350   b  and released to the outside of the photoelectric conversion device  1   b , and light L 3  which is a remaining portion of the light L 1  may pass through the semi-permeable metal layer  350   b  and enter the stacked structure ST. The light L 3  incident into the stacked structure ST may be repeatedly reflected between the reflective layer  310  and the semi-permeable metal layer  350   b , and light L 4  which is a portion of the light L 3  may pass through the semi-permeable metal layer  350   b  to be released to the outside while the remaining portion of the light L 3  is reflected towards the reflective layer  310 . 
     In an embodiment, the light L 1  incident on the photoelectric conversion device  1   b  through the microlens  370  may be focused on the recess  350 R of the semipermeable metal layer  350   b  vertically overlapping the center portion of the microlens  370 , and a portion of the semi-permeable metal layer  350   b  exposed at the bottom surface of the plurality of recesses  350 R may have a relatively high light transmittance, so that a relatively large amount of the light L 1  incident on the photoelectric conversion device  1   b  through the microlens  370  may be incident into the stacked structure ST, thereby increasing the light conversion efficiency of the photoelectric conversion device  1   b.    
       FIG. 4A  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts, and  FIG. 4B  is a plan layout illustrating some of components of the photoelectric conversion device. In  FIGS. 4A and 4B , the same reference numerals as in  FIG. 1  denote the same components, and the duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to  FIGS. 4A and 4B  together, a photoelectric conversion device  2  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340   a , and a semi-permeable metal layer  350   c . A stacked structure STa may include the photoelectric conversion layer  320 , the transparent electrode layer  330 , and an insulating optical spacer  340   a . The photoelectric conversion device  2  may further include the passivation layer  360  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   a  may have a trench  340 Ra. The trench  340 Ra may extend inward from a top surface of the insulating optical spacer  340   a  toward a bottom surface thereof, but may not extend to the bottom surface thereof. The trench  340 Ra may be arranged to overlap the edges of the plurality of microlenses  370  in the vertical direction (e.g., in a direction parallel to the thickness direction of the substrate  100 ). The trench  340 Ra may be disposed on the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2  and may extend therebetween. 
     The semi-permeable metal layer  350   c  may be formed on the insulating optical spacer  340   a . The semi-permeable metal layer  350   c  may cover the insulating optical spacer  340   a . The trench  340 Ra may be filled by a light blocking wall  350 Ec. In an embodiment, the light blocking wall  350 Ec may include the same material as the semi-permeable metal layer  350   c . For example, the light blocking wall  350   c  and the semi-permeable metal layer  350   c  may be formed together to be one integrated body, and the light blocking wall  350   c  may be a portion of the integrated body for filling the trench  340 Ra and the semi-permeable metal layer  350   c  may be a portion of the integrated body for covering the top surface of the insulating optical spacer  340   a  except the trench  340 Ra. The semi-permeable metal layer  350   c  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  2 . The semi-permeable metal layer  350   c  may have the sixth thickness T 6 . The passivation layer  360  may be formed on the semi-permeable metal layer  350   c  and the light blocking wall  350   c.    
     Light L 2 , which is a portion of light L 1  incident on the photoelectric conversion device  2  through the microlenses  370 , may be reflected on the semi-permeable metal layer  350   c  and released to the outside of the photoelectric conversion device  2 , and light L 3  which is a remaining portion of light L 1  may pass through the semi-permeable metal layer  350   c  and enter the stacked structure ST. The light L 3  incident into the stacked structure ST may be repeatedly reflected between the reflective layer  310  and the semi-permeable metal layer  350   c , and light L 4 , which is a portion of the light L 3 , may pass through the semi-permeable metal layer  350   c  to be released to the outside and a remaining portion of the light L 3  may be reflected towards the reflective layer  310 . The light blocking wall  350 Ec may extend between the plurality of pixel regions, so that the light incident on one pixel region, for example, the first pixel region PX 1 , may be blocked to enter an adjacent pixel region, for example, the second pixel region PX 2 . Therefore, the light blocking wall  350 Ec may prevent optical interference from occurring between adjacent pixel regions of the plurality of pixels of the photoelectric conversion device  2 , thereby increasing the light detection resolution of the photoelectric conversion device  2 . 
       FIG. 5  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts. In  FIG. 5 , the same reference numerals as in  FIGS. 1, 4A and 4B  denote the same components, and the duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to  FIG. 5 , a photoelectric conversion device  2   a  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340   a , and a semi-permeable metal layer  350   d . The photoelectric conversion device  2   a  may further include the passivation layer  360  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   a  may have the trench  340 Ra. The trench  340 Ra may extend along edges of the plurality of microlenses  370  in a plan view. The trench  340 Ra may be arranged to overlap the edge of the plurality of microlenses  370  in the vertical direction. The trench  340 Ra may be disposed on the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 , and may extend therebetween. 
     The semi-permeable metal layer  350   d  may be formed on the insulating optical spacer  340   a . The semi-permeable metal layer  350   d  may be formed to conformally cover the insulating optical spacer  340   a . A portion of the trench  340 Ra of the insulating optical spacer  340   a  may be filled with a light blocking wall  350 Ed conformally covering an inner sidewall and a bottom surface of the trench  340 Ra. As shown in the embodiment of  FIG. 5 , the light blocking wall  350 Ed may not entirely fill the trench  340 Ra. The light blocking wall  350 Ed may include the same material as the semi-permeable metal layer  350   d . The light blocking wall  350 Ed and the semi-permeable metal layer  350   d  may be formed together to be one integrated body, and the light blocking wall  350 Ed may be a portion of the integrated body for filling a portion of the trench  340 Ra and the semi-permeable metal layer  350   d  may be a portion of the integrated body for covering the top surface of the insulating optical spacer  340   a  except the trench  340 Ra. The semi-permeable metal layer  350   d  may have the sixth thickness T 6 . 
     The semi-permeable metal layer  350   d  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  2   a . For example, in an embodiment, the light transmittance of the semi-permeable metal layer  350   d  may be in a range of about 30% to about 70% for the light of the wavelength band to be detected by the photoelectric conversion device  2   a.    
     A passivation layer  360   c  may be formed on the semi-permeable metal layer  350   d  and the light blocking wall  350 Ed. The passivation layer  360   c  may have an extension buried portion  360 Ec that entirely fills a remaining portion of the trench  340 Ra, such as the remaining portion of the trench  340 Ra that is not filled with the light blocking wall  350 Ed. As shown in the embodiment of  FIG. 5 , the remaining portion of the trench  340 Ra that is not filled by the light blocking wall  350 Ed may be in a central portion of the trench  340 Ra in a direction parallel to an upper surface of the substrate  100 . 
     Light L 2 , which is a portion of light L 1  incident on the photoelectric conversion device  2   a  through the microlenses  370 , may be reflected on the semi-permeable metal layer  350   d  and released to the outside of the photoelectric conversion device  2   a , and light L 3  which a remaining portion of light L 1  may pass through the semi-permeable metal layer  350   d  and enter the stacked structure ST. The light L 3  incident into the stacked structure ST may be repeatedly reflected between the reflective layer  310  and the semi-permeable metal layer  350   d , and light L 4  which is a portion of light L 3  may pass through the semi-permeable metal layer  350   d  to be released to the outside and the remaining portion of light L 3  may be reflected towards the reflective layer  310 . The light blocking wall  350 Ed may extend between the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 , so that the light incident on one pixel region, for example, the first pixel region PX 1 , may be blocked to enter an adjacent pixel region, for example, the second pixel region PX 2 . Therefore, the light blocking wall  350 Ed may prevent optical interference from occurring between adjacent pixels of the plurality of pixels of the photoelectric conversion device  2   a , thereby increasing the light detection resolution of the photoelectric conversion device  2   a.    
       FIGS. 6A and 6B  are cross-sectional views illustrating main parts of a photoelectric conversion device according to embodiments of the present inventive concept. In  FIGS. 6A and 6B , the same reference numerals as in  FIGS. 1 to 5  denote the same components, and the duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to  FIG. 6A , a photoelectric conversion device  3  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340   a , and a semi-permeable metal layer  350   e . The photoelectric conversion device  3  may further include the passivation layer  360   a  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   a  may have the trench  340 Ra. The trench  340 Ra may be arranged to overlap the edge of the plurality of microlenses  370  in the vertical direction. The trench  340 Ra may be disposed on the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2  and may extend therebetween. 
     The semi-permeable metal layer  350   e  may be formed on the insulating optical spacer  340   a . The semi-permeable metal layer  350   e  may cover a portion of the insulating optical spacer  340   a . The trench  340 Ra may be filled by the light blocking wall  350 Ec. The semi-permeable metal layer  350   e  may include the plurality of openings  3500 . The plurality of openings  3500  may fully penetrate the semi-permeable metal layer  350   e , and thus, the insulating optical spacer  340   a  may be exposed on the bottom surface of the plurality of openings  3500 . The plurality of openings  3500  may be in the center portion of the plurality of microlenses  370  in a plan view (e.g., in a direction parallel to an upper surface of the substrate  100 ). The plurality of openings  3500  may be arranged to overlap the center portion of the plurality of microlenses  370  in the vertical direction. 
     The semi-permeable metal layer  350   e  may have the sixth thickness T 6 . The semi-permeable metal layer  350   e  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  3 . For example, in an embodiment, the light transmittance of the semi-permeable metal layer  350   e  may be in a range of about 30% to about 70% for the light of the wavelength band to be detected by the photoelectric conversion device  3 . 
     The passivation layer  360   a  may be formed on the semi-permeable metal layer  350   e  and the light blocking wall  350 Ec. The passivation layer  360   a  may fill the plurality of openings  3500  and have a plurality of extension portions  360 Ea extending toward the insulating optical spacer  340   a . Each of the plurality of extension portions  360 Ea of the passivation layer  360   a  may directly contact the insulating optical spacer  340   a.    
     The photoelectric conversion device  3  according to an embodiment of the present inventive concepts may have the light blocking wall  350 Ec and the plurality of openings  3500 , so that light detection resolution and light conversion efficiency may be increased. 
     Referring to  FIG. 6B , a photoelectric conversion device  3   a  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340   a , and a semi-permeable metal layer  350   f . The photoelectric conversion device  3   a  may further include the passivation layer  360   b  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   a  may have the trench  340 Ra. The trench  340 Ra may be arranged to overlap the edges of the plurality of microlenses  370  in the vertical direction. The trench  340 Ra may be disposed on the plurality of pixel regions, such as the first and second pixel regions PX 1 , PX 2  and may extend therebetween. 
     The semi-permeable metal layer  350   f  may be formed on the insulating optical spacer  340   a  (e.g., directly thereon in a thickness direction of the substrate  100 ). The semi-permeable metal layer  350   f  may cover the insulating optical spacer  340   a . The trench  340 Ra may be filled by the light blocking wall  350 Ec. The semi-permeable metal layer  350   f  may have the plurality of recesses  350 R. The plurality of recesses  350 R may extend toward the bottom surface of the semi-permeable metal layer  350   f . The plurality of recesses  350 R may not fully penetrate the semi-permeable metal layer  350   f . The plurality of recesses  350 R may be in the center portion of the plurality of microlenses  370  in a plan view (e.g., in a direction parallel to an upper surface of the substrate  100 ). The plurality of recesses  350 R may be arranged to overlap the center portion of the plurality of microlenses  370  in the vertical direction (e.g., a direction parallel to a thickness direction of the substrate  100 ). 
     The insulating optical spacer  340   a  may not be exposed on the bottom surface of the plurality of recesses  350 R and a portion of the semi-permeable metal layer  350   f  may be exposed. The portion of the semi-permeable metal layer  350   f  exposed on the bottom surface of the plurality of recesses  350 R may have a relatively thin thickness. The portion of the semi-permeable metal layer  350   f  exposed on the bottom surface of the plurality of recesses  350 R may have a light transmittance greater than a remaining portion of the semi-permeable metal layer  350   f . The semi-permeable metal layer  350   f  may have the sixth thickness T 6  in the remaining portion, except for a portion of the semi-permeable metal layer  350   f  exposed at the bottom surface of the plurality of recesses  350 R. The portion of the semi-permeable metal layer  350   f  exposed on the bottom surface of the plurality of recesses  350 R may have a thickness that is less than the sixth thickness T 6 . 
     The passivation layer  360   b  may be formed on the semi-permeable metal layer  350   f  and the light blocking wall  350 Ec (e.g., directly thereon in a thickness direction of the substrate  100 ). The passivation layer  360   b  may fill the plurality of recesses  350 R and have the plurality of extension portions  360 Eb extending toward the insulating optical spacer  340   a . Each of the plurality of extension portions  360 Eb of the passivation layer  360   b  may be spaced apart from the insulating optical spacer  340  without contacting the optical spacer  340 . For example, as shown in the embodiment of  FIG. 6B , the exposed portion of the plurality of recesses  350 R may be interposed between the insulating optical spacer  340   a  and the plurality of extension portions  360 Eb in a thickness direction of the substrate  100 . 
     The photoelectric conversion device  3   a  according to an embodiment of the present inventive concepts may have the light blocking wall  350 Ec and the plurality of recesses  350 R, so that light detection resolution and light conversion efficiency may be increased. 
       FIGS. 7A and 7B  are cross-sectional views illustrating main parts of a photoelectric conversion device according to embodiments of the present inventive concepts. In  FIGS. 7A  and  7 B, the same reference numerals as in  FIGS. 1 to 6B  denote the same components, and the duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to  FIG. 7A , the photoelectric conversion device  3   b  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340   a , and a semi-permeable metal layer  350   g . The photoelectric conversion device  3   b  may further include the passivation layer  360   d  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   a  may have the trench  340 Ra. The trench  340 Ra may be arranged to overlap the edges of the plurality of microlenses  370  in the vertical direction (e.g., in a direction parallel to a thickness direction of the substrate  100 ). The trench  340 Ra may be disposed on the plurality of pixel regions, such as the first and second pixel regions PX 1 , PX 2  and may extend therebetween. 
     The semi-permeable metal layer  350   g  may be formed on the insulating optical spacer  340   a . The semi-permeable metal layer  350   g  may cover a portion of the insulating optical spacer  340   a . A portion of the trench  340 Ra may be filled by the light blocking wall  350 Ed. The semi-permeable metal layer  350   g  may include the plurality of openings  3500 . The plurality of openings  3500  may fully penetrate the semi-permeable metal layer  350   g , and thus, the insulating optical spacer  340   a  may be exposed on the bottom surface of the plurality of openings  3500 . The plurality of openings  3500  may be in the center portion of the plurality of microlenses  370  in a plan view (e.g., in a direction parallel to an upper surface of the substrate  100 ). The plurality of openings  3500  may be arranged to overlap the center portion of the plurality of microlenses  370  in the vertical direction (e.g., in a direction parallel to a thickness direction of the substrate  100 ). 
     The semi-permeable metal layer  350   g  may have the sixth thickness T 6 . The semi-permeable metal layer  350   g  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  3   b . For example, in an embodiment, the light transmittance of the semi-permeable metal layer  350   g  may be in a range of about 30% to about 70% for the light of the wavelength band to be detected by the photoelectric conversion device  3   b.    
     A passivation layer  360   d  may be formed on the semi-permeable metal layer  350   g  and the light blocking wall  350 Ed (e.g., directly thereon in a thickness direction of the substrate  100 ). The passivation layer  360   d  may include the plurality of extension portions  360 Ea that fill the plurality of openings  3500  and extend toward the insulating optical spacer  340   a , and the extended buried portion  360 Ec that entirely fills the remaining portion of the trench  340 Ra which is not filled by the light blocking wall  350 Ed. Each of the plurality of extension portions  360 Ea of the passivation layer  360   d  may directly contact the insulating optical spacer  340   a.    
     The photoelectric conversion device  3   b  according to an embodiment of the present inventive concepts may have the light blocking wall  350 Ed and the plurality of openings  3500 , so that light detection resolution and light conversion efficiency may be increased. 
     Referring to  FIG. 7B , the photoelectric conversion device  3   c  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , the insulating optical spacer  340   a , and a semi-permeable metal layer  350   h . The photoelectric conversion device  3   c  may further include the passivation layer  360   e  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   a  may have the trench  340 Ra. The trench  340 Ra may be arranged to overlap the edges of the plurality of microlenses  370  in the vertical direction (e.g., in a direction parallel to a thickness direction of the substrate  100 ). The trench  340 Ra may be disposed on the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2  and may extend therebetween. 
     The semi-permeable metal layer  350   h  may be formed on the insulating optical spacer  340   a  (e.g., directly thereon in a thickness direction of the substrate  100 ). The semi-permeable metal layer  350   h  may cover the insulating optical spacer  340   a . A portion of the trench  340 Ra may be filled by the light blocking wall  350 Ed. The semi-permeable metal layer  350   h  may have the plurality of recesses  350 R. The plurality of recesses  350 R may extend toward the bottom surface of the semi-permeable metal layer  350   h . The plurality of recesses  350 R may not fully penetrate the semi-permeable metal layer  350   h . The plurality of recesses  350 R may be in the center portion of the plurality of microlenses  370  in a plan view (e.g., in a horizontal direction parallel to an upper surface of the substrate  100 ). The plurality of recesses  350 R may be arranged to overlap the center portion of the plurality of microlenses  370  in the vertical direction (e.g., in a direction parallel to a thickness direction of the substrate  100 ). 
     The insulating optical spacer  340   a  may be not exposed on the bottom surface of the plurality of recesses  350 R and a portion of the semi-permeable metal layer  350   h  may be exposed. The portion of the semi-permeable metal layer  350   h  exposed on the bottom surface of the plurality of recesses  350 R may have a relatively thin thickness. The portion of the semi-permeable metal layer  350   h  exposed on the bottom surface of the plurality of recesses  350 R may have a light transmittance greater than a remaining portion of the semi-permeable metal layer  350   h . The semi-permeable metal layer  350   h  may have the sixth thickness T 6  in the remaining portion, except a portion of the semi-permeable metal layer  350   h  exposed at the bottom surface of the plurality of recesses  350 R. The portion of the semi-permeable metal layer  350   h  exposed on the bottom surface of the plurality of recesses  350 R may have a thickness less than the sixth thickness T 6 . 
     A passivation layer  360   e  may be formed on the semi-permeable metal layer  350   h  and the light blocking wall  350 Ed (e.g., directly thereon in a thickness direction of the substrate  100 ). The passivation layer  360   e  may include the plurality of extension portions  360 Eb that fill the plurality of recesses  350 R and extend toward the insulating optical spacer  340   a , and the extended buried portion  360 Ec that entirely fills the remaining portion of the trench  340 Ra that is not filled by the light blocking wall  350 Ed. The passivation layer  360   e  may be spaced apart from the insulating optical spacer  340   a  without contacting the insulation optical spacer  340   a.    
     The photoelectric conversion device  3   c  according to an embodiment of the present inventive concepts may have the light blocking wall  350 Ed and the plurality of recesses  350 R, so that light detection resolution and light conversion efficiency may be increased. 
       FIG. 8  is a cross-sectional view illustrating main parts of a photoelectric conversion device according to an embodiment of the present inventive concepts. In  FIG. 8 , the same reference numerals as in  FIGS. 1 to 7B  denote the same components, and the duplicate descriptions thereof are omitted for convenience of explanation. 
     Referring to the embodiment of  FIG. 8 , the photoelectric conversion device  4  may include the substrate  100 , the wiring layer  200 , the plurality of reflective layers  310 , the photoelectric conversion layer  320 , the transparent electrode layer  330 , an insulating optical spacer  340   b , and a semi-permeable metal layer  350   i . A stacked structure STb may include the photoelectric conversion layer  320 , the transparent electrode layer  330 , and an insulating optical spacer  340   b . The photoelectric conversion device  4  may further include the passivation layer  360   f  and the plurality of microlenses  370 . 
     The insulating optical spacer  340   b  may have at least one pixel recess  340 Rb. In an embodiment, each of the at least one pixel recesses  340 Rb may be formed to correspond to at least one pixel region of the plurality of the plurality of pixel regions, respectively, such as the first pixel region PX 1  and/or the second pixel region PX 2 . The at least one pixel recess  340 Rb may be formed by forming the insulating optical spacer  340   b  to have a relatively lower top surface over the entire pixel region of at least one of the plurality of pixel regions, such as the first and/or second pixel regions PX 1 , PX 2 . For example, as shown in the embodiment of  FIG. 8 , the pixel recess  340 Rb may be formed to correspond to the first pixel region PX 1 , and the top surface of a portion of the insulating optical spacer  340   b  disposed in the first pixel region PX 1  may be disposed at a lower vertical level than the top surface of the other portion of the insulating optical spacer  340   b  disposed in the second pixel region PX 2 . However, embodiments of the present inventive concepts are not limited thereto. 
     The insulating optical spacer  340   b  may have the fourth thickness T 4  in the portion where the at least one pixel recess  340 Rb is formed, and may have a seventh thickness  17  in the remaining other portion. The seventh thickness T 7  may be greater than the fourth thickness T 4 . A first stacked portion STb 1 , which is the portion which includes the at least one pixel recess  340 Rb among the stacked structure STb that is formed of the photoelectric conversion layer  320 , the transparent electrode layer  330 , and the insulating optical spacer  340   b , may have the fifth thickness T 5 , and a second stacked portion STb 2 , which is the remaining portion that does not include the at least one pixel recess  340 Rb, may have an eighth thickness T 8 . The eighth thickness T 8  may be greater than the fifth thickness T 5 . 
     A semi-permeable metal layer  350   i  may be formed on the insulating optical spacer  340   b  (e.g., directly thereon in a thickness direction of the substrate  100 ). The semi-permeable metal layer  350   i  may cover the insulating optical spacer  340   b . In some embodiments, the semi-permeable metal layer  350   i  may be conformally formed to have the sixth thickness T 6 , which is generally the same thickness in each of the first pixel region PX 1  and the second pixel region PX 2 . The semi-permeable metal layer  350   i  may have a third portion  350   ic  on a side surface of the pixel recess  340 Rb having a thickness that is greater than the sixth thickness T 6 . For example, the semi-permeable metal layer  350   i  may conformally cover a bottom surface and inner side walls of the pixel recess  340 Rb. In some embodiments, the semi-permeable metal layer  350   i  may be formed so as not to entirely fill the pixel recess  340 Rb. 
     The semi-permeable metal layer  350   i  may include a first portion  350   ia  covering the bottom surface of the pixel recess  340 Rb. For example, the semi-permeable metal layer  350   i  may cover a top surface of the insulating optical spacer  340   b  that is located at a relatively lower vertical level due to the pixel recess  340 Rb as compared to the semi-permeable metal layer  350   i  disposed in another pixel region. The semi-permeable metal layer  350   i  may include a second portion  350   ib  covering the top surface of the insulating optical spacer  340   b  in a region other than the pixel recess  340 Rb. The second portion  350   ib  is located at a relatively higher vertical level than the first portion  350   ia . The semi-permeable metal layer  350   i  includes a third portion  350   ic  covering a side surface of the pixel recess  340 Rb which extends from the first portion  350   ia  to the second portion  350   ib.    
     The semi-permeable metal layer  350   i  may have semi-permeability for light of the wavelength band to be detected by the photoelectric conversion device  4 . For example, in an embodiment, the light transmittance of the semi-permeable metal layer  350   i  may be in a range of about 30% to about 70% for the light of the wavelength band to be detected by the photoelectric conversion device  4 . 
     The passivation layer  360   f  may be formed on the semi-permeable metal layer  350   i  (e.g., directly thereon in a thickness direction of the substrate  100 ). The passivation layer  360   f  may have an extension buried portion  360 Ef that entirely fills a remaining portion of the pixel recesses  340 Rb, that is not filled with the semi-permeable metal layer  350   i.    
     Light L 2   a , which is a portion of light L 1   a  incident on the first pixel region PX 1  of the photoelectric conversion device  4  through the microlens  370 , may be reflected on the first portion  350   ia  of the semi-permeable metal layer  350   i  that covers the bottom surface of the pixel recess  340 Rb and released to the outside of the photoelectric conversion device  4 , and light L 3   a  which is a remaining portion of light L 1   a  may pass through the first portion  350   ia  of the semi-permeable metal layer  350   i  and enter the first stacked portion STb 1  of the stacked structure STb. Light L 2   b , which is a portion of light L 1   b  incident on the second pixel region PX 2  of the photoelectric conversion device  4  through the microlens  370 , may be reflected on the second portion  350   ib  of the semi-permeable metal layer  350   i  and released to the outside of the photoelectric conversion device  4 , and light L 3   b  which is a remaining portion of light L 1   b  may pass through the second portion  350   ib  of the semi-permeable metal layer  350   i  and enter the second stacked portion STb 2  of the stacked structure STb. The third portion  350   ic  of the semi-permeable metal layer  350   i  may prevent optical interference from occurring between the plurality of pixels of the photoelectric conversion device  4 . 
     The first stacked portion STb 1  may have the fifth thickness T 5  and the second stacked portion STb 2  may have the eighth thickness T 8  greater than the fifth thickness T 5 , so that light having a wavelength corresponding to the fifth thickness T 5  among light L 3   a  which is a remaining portion of the first light L 1   a  incident on the first stacked portion STb 1  may cause a resonance in the first stacked portion STb 1 , and the light having a wavelength corresponding to the eighth thickness T 8  of light L 3   b  which is a remaining portion of the second light L 1   b  incident on the second stacked portion STb 2  may cause the resonance in the second stacked portion STb 2 . 
     Accordingly, the photoelectric conversion device  4  according to an embodiment of the present inventive concepts may increase the light conversion efficiency and the light detection resolution, and perform the function of the multi-spectrum photoelectric conversion device capable of detecting light having other wavelength bands. 
       FIGS. 9A, 9B, 10A, 10B, 11, 12A, and 12B  are cross-sectional views illustrating a method of manufacturing a photoelectric conversion device according to embodiments of the inventive concept. In  FIGS. 9A, 9B, 10A, 10B, 11, 12A and 12B , the same reference numerals as in  FIGS. 1 to 7B  denote the same components, and the duplicate descriptions thereof are omitted. 
     Referring to  FIG. 9A , the wiring layer  200  and the plurality of reflective layers  310  may be sequentially formed on the substrate  100 , and the photoelectric conversion layer  320 , the transparent electrode layer  330  and the insulating optical spacer  340  may be sequentially formed on the plurality of reflective layers  310  to form the stacked structure ST. 
     Referring to  FIG. 9B , the semi-permeable metal layer  350  covering the stacked structure ST may be formed. As shown in  FIG. 1 , the passivation layer  360  and the plurality of microlenses  370  may be subsequently disposed thereon to form the photoelectric conversion device  1 . 
     Referring to  FIG. 10A , a portion of the semi-permeable metal layer  350  shown in  FIG. 9B  may be removed to form the semi-permeable metal layer  350   a  having the plurality of openings  3500 , through which the top surface of the insulating optical spacer  340  is exposed. As shown in  FIG. 2A , the passivation layer  360   a  and the plurality of microlenses  370  may subsequently disposed thereon to form the photoelectric conversion device  1   a.    
     Referring to  FIG. 10B , a portion of the semi-permeable metal layer  350  shown in  FIG. 9B  may be removed to form the semi-permeable metal layer  350   b  having the plurality of recesses  350 R, through which the top surface of the insulating optical spacer  340  is not exposed. As shown in  FIG. 3A , the passivation layer  360  and the plurality of microlenses  370  may subsequently disposed thereon to form the photoelectric conversion device  1   b.    
     Referring to  FIG. 11 , a portion of the insulating optical spacer  340  shown in  FIG. 9A  may be removed to form the insulating optical spacer  340   a  having the trench  340 Ra. As shown in  FIG. 4A , the semi-permeable metal layer  350   c  having the light blocking wall  350 Ec that fills the trench  340 Ra, the passivation layer  360   b , and the plurality of microlens  370  may be subsequently disposed thereon to form the photoelectric conversion device  2 . In an embodiment, as shown in  FIG. 5 , the semi-permeable metal layer  350   d  having the light blocking wall  350 Ed that fills a portion of the trench  340 Ra, the passivation layer  360   c  having the extension buried portion  360 Ec that entirely fills the remaining portion of the trench  340 Ra, and the plurality of microlens  370  may be subsequently disposed thereon to form the photoelectric conversion device  2   a.    
     Referring to  FIG. 12A , the wiring layer  200  and the plurality of reflective layers  310  may be sequentially formed on the substrate  100 , and subsequently the photoelectric conversion layer  320 , the transparent electrode layer  330 , and a preliminary insulating layer  340   p  may be sequentially formed on the plurality of reflective layers  310 . 
     Referring to  FIGS. 12A and 12B  together, a portion of the preliminary insulating layer  340   p  may be removed to form the insulating optical spacer  340   b  having at least one pixel recess  340 Rb. As shown in  FIG. 8 , the semi-permeable metal layer  350   i , the passivation layer  360   f  and the plurality of microlenses  370  may be subsequently disposed thereon to form the photoelectric conversion device  4 . 
     It is obvious to those skilled in the art that the photoelectric conversion devices  3 ,  3   a ,  3   b , and  3   c  shown in  FIGS. 6A to 7B  may also be formed with reference to  FIGS. 9A to 12 , and a detailed description thereof will be omitted for convenience of explanation. 
       FIG. 13  is a block diagram illustrating a configuration of a photoelectric conversion device according to an embodiment of the present inventive concepts. 
     Referring to  FIG. 13 , a photoelectric conversion device  1100  may include a pixel array  1110 , a controller  1130 , a row driver  1120 , and a pixel signal processing unit  1140 . The photoelectric conversion device  1100  may include at least one of the photoelectric conversion devices  1 ,  1   a ,  1   b ,  2 ,  2   a ,  3 ,  3   a ,  3   b ,  3   c , and  4  described in  FIGS. 1 to 8 . 
     The pixel array  1110  may include a plurality of unit pixels arranged in two dimensions, and each unit pixel may include a photoelectric conversion layer. The photoelectric conversion layer may absorb light to generate charges, and an electrical signal (e.g., output voltage) according to the generated charges may be provided to the pixel signal processing unit  1140  through vertical signal lines. In an embodiment, the unit pixels included in the pixel array  1110  may provide an output voltage one at a time in a row unit, thereby, the unit pixels belonging to any one row of the pixel array  1110  may be activated simultaneously by a selection signal out from the row driver  1120 . The unit pixels belonging to the row to be selected may provide the output voltage according to the absorbed light to an output line of a corresponding column. 
     The controller  1130  may control the row driver  1120  so that the pixel array  1110  absorbs the light and accumulates the charges, temporarily stores the accumulated charges, and outputs the electrical signal according to the stored charges to the outside of the pixel array  1110 . Further, the controller  1130  may control the pixel signal processing unit  1140  to measure the output voltage to be provided by the pixel array  1110 . 
     As shown in the embodiment of  FIG. 13 , the pixel signal processing unit  1140  may include a correlated double sampler (CDS)  1142 , an analog-to-digital converter (ADC)  1144 , and a buffer  1146 . The correlation dual sampler  1142  may sample and hold the output voltage provided by the pixel array  1110 . The correlation dual sampler  1142  may double sample a specific noise level and a level according to the generated output voltage, and output a level corresponding to the difference therebetween. In addition, the correlation dual sampler  1142  may receive a lamp signal generated by a lamp signal generator  1148  and compare to each other to output the comparison result. The analog-to-digital converter  1144  may convert an analog signal corresponding to the level received from the correlation dual sampler  1142  into a digital signal. The buffer  1146  may latch the digital signal, and the latched signal may be sequentially output to the outside of the photoelectric conversion device  1100  and transmitted to an image processor. 
       FIG. 14  is a block diagram illustrating a configuration of a photoelectric conversion device according to an embodiment of the present inventive concepts. 
     Referring to  FIG. 14 , in an embodiment, a photoelectric conversion element  2000  may include a pixel portion  2200  and a peripheral circuit portion. The pixel portion  2200  may be formed by regularly arranging a plurality of pixel  2100  in a substrate  2010  in a two-dimensional array structure, the plurality of pixel  2100  including a photoelectric conversion layer. The photoelectric conversion device  2000  may include at least one of the photoelectric conversion devices  1 ,  1   a ,  1   b ,  2 ,  2   a ,  3 ,  3   a ,  3   b ,  3   c , and  4  described in  FIGS. 1 to 8 . 
     The peripheral circuit portion may be disposed around the pixel portion  2200  and include a vertical drive circuit  2400 , a column signal processing circuit  2500 , a horizontal drive circuit  2600 , an output circuit  2700 , and a control circuit  2800 . 
     The control circuit  2800  may control the vertical drive circuit  2400 , the column signal processing circuit  2500 , and the horizontal drive circuit  2600 , and the like. For example, in an embodiment, the control circuit  2800  may generate a vertical synchronization signal, a horizontal synchronization signal, and clock or control signals that serve as a reference for operations of the vertical drive circuit  2400 , the column signal processing circuit  2500 , and the horizontal drive circuit  2600 , and the like, based on a master clock. In addition, the control circuit  2800  may input the clock or control signals to the vertical drive circuit  2400 , the column signal processing circuit  2500 , and the horizontal drive circuit  2600 , and the like. 
     In an embodiment, the vertical drive circuit  2400  may include, for example, a shift register, in which the pixel may be driven in a row unit, by selecting a pixel driving wiring and supplying a pulse for driving the pixel to the selected pixel driving wiring. For example, the vertical drive circuit  2400  may sequentially and selectively scan the pulse to each pixel  2100  of the pixel portion  2200  in the vertical direction in row unit. Further, through the vertical signal line  2320 , the pixel signal according to the charges generated in the photoelectric conversion layer of each pixel  2100  may be supplied to the column signal processing circuit  2500 . 
     The column signal processing circuit  2500  may be arranged for each column of the pixel  2100  and perform signal processing such as noise removal for each pixel column of signals output from the pixel  2100  for one column. For example, the column signal processing circuit  2500  may perform the signal processing, such as a correlated double sampling or signal amplification, AD conversion, and the like for removing the noise inherent in the pixels  2100 . In an embodiment, the horizontal selection switch may be provided at an output terminal of the column signal processing circuit  2500 . 
     The horizontal drive circuit  2600  may include, for example, the shift register, and by sequentially outputting a horizontal scan pulse, the horizontal drive circuit  2600  may output the pixel signal of each of the column signal processing circuit  2500  to a horizontal signal line  2340  through the selection of each of the column signal processing circuits  2500  in order. 
     An output circuit  2700  may perform signal processing and output for signals that are sequentially supplied through the horizontal signal line  2340  in each of the column signal processing circuits  2500 . For example, the output circuit  2700  may only perform buffering, or may perform black level adjustment, thermal uneven calibration, various digital signal processing, and the like. On the other hand, an input/output terminal  2900  may exchange signals with the outside. 
       FIG. 15  is a lead-out circuit diagram of a photoelectric conversion device according to an embodiment of the present inventive concepts. 
     Referring to  FIG. 15 , a plurality of pixels PX may be arranged in a matrix form. Each of the plurality of pixels PX may include three logic transistors. In an embodiment, the logic transistors may include a reset transistor RX, a selection transistor SX, and a drive transistor DX (or a source follower transistor). Each of the plurality of pixels PX may further include a photoelectric conversion layer PCL and a floating diffusion region FD. 
     The plurality of pixels PX may correspond to the plurality of pixel regions, such as the first and second pixel regions PX 1  and PX 2 , described in  FIGS. 1 to 8 . The logic transistors RX, SX, and DX may be implemented by the plurality of transistors TR described in  FIGS. 1 to 8 . The photoelectric conversion layer PCL may be implemented by the photoelectric conversion layer  320  described in  FIGS. 1 to 8 . FIG. The photoelectric conversion layer PCL may generate and accumulate light charges in proportion to the amount of light incident from the outside. In some embodiments, the floating diffusion region FD may be implemented by the impurity region  120  described in  FIGS. 1 to 8 . 
     A gate terminal of the drive transistor DX may be connected to the floating diffusion region FD. The drive transistor DX may operate as a source follower buffer amplifier by charges accumulated in the floating diffusion region FD and amplify the potential change in the floating diffusion region FD and output the same as the output voltage VOUT to a column line. 
     In an embodiment, the selection transistor SX may select the plurality of pixels PX in row units, and when the selection transistor SX is turned on, the power supply voltage VDD may be delivered to a source electrode of the drive transistor DX. A row driver may operate by a selection control signal SEL to be input, and switching and addressing operations may be performed. When the selection control signal SEL is applied from the row driver, the output voltage VOUT may be output to the column line connected to the selection transistor SX. 
     The reset transistor RX may periodically reset the charges accumulated in the floating diffusion region FD. A drain electrode of the reset transistor RX may be connected to the floating diffusion region FD, and the row driver may reset a voltage of the floating diffusion region FD into a lead-out voltage VRD by a reset control signal RG to be input in the row driver. 
     A cathode connected to the photoelectric conversion layer PCL may be connected to the floating diffusion region FD and an anode connected to the photoelectric conversion layer PCL may be connected to an upper electrode voltage VT. In an embodiment, the photoelectric conversion layer PCL may use holes as a main charge carrier, and therefore, the drain electrode of the reset transistor RX may be connected to the power supply voltage VDD and the other lead voltage VRD. 
     While the present inventive concepts have been particularly shown and described with reference to non-limiting embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the present inventive concepts.