Patent Description:
In recent years, infrared sensors configured to detect light in infra-red wavelength spectrum have been researched to improve sensitivity of the sensors in low-illumination environments or for use as a biometric or authentication device. Silicon photodiodes may be used as infrared sensors. However, although silicon is configured to absorb light in a near-infrared wavelength spectrum of less than about <NUM> from a visible wavelength spectrum, there is a limit in absorbing light in the near-infrared wavelength spectrum of greater than or equal to about <NUM>.

<CIT> discloses an organic photodetector for detecting infrared, visible and UV radiation with a tunable spectral response.

Some example embodiments provide one or more sensors that may be effectively used to sense light in an infrared wavelength spectrum of greater than or equal to about <NUM>.

Some example embodiments provide one or more electronic devices including the one or more sensors.

According to a first aspect of the invention, a sensor is as defined in claim <NUM>. An external quantum efficiency (EQE) spectrum in the second infrared wavelength region is amplified, such that a variance of a local maximum EQE value (EQEmax) of the EQE spectrum from a remainder of EQE values of the EQE spectrum in the second infrared wavelength region is greater than a variance of the second absorption peak from a remainder of absorption intensities of the second absorption spectrum in the second infrared wavelength region, and/or a full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region is narrower than a full width at half maximum (FWHM) of the second absorption spectrum in the second infrared wavelength region.

In some embodiments, a difference between a wavelength at the second absorption peak of the second absorption spectrum and a wavelength at the first absorption peak of the first absorption spectrum may be greater than or equal to about <NUM>.

In some embodiments, the wavelength at the first absorption peak of the first absorption spectrum may be within with a range of about <NUM> to about <NUM>. The wavelength at the second absorption peak of the second absorption spectrum may be within a separate range of about <NUM> to about <NUM>.

In some embodiments, a first absorption intensity at the first absorption peak of the first absorption spectrum and a second absorption intensity at the second absorption peak of the second absorption spectrum may satisfy Relationship Equation <NUM>: <MAT> wherein, in Relationship Equation <NUM>,.

In some embodiments, the FWHM of the EQE spectrum in the second infrared wavelength region may be narrower than a FWHM of the EQE spectrum in the first infrared wavelength region.

In some embodiments, the FWHM of the EQE spectrum in the second infrared wavelength region may be within a range of about <NUM> to about <NUM>.

In some embodiments, the local maximum EQE value may be greater than or equal to about <NUM>%.

In some embodiments, the sensor may further include a buffer layer between the first electrode and the light absorbing layer or between the second electrode and the light absorbing layer.

In some embodiments, a peak wavelength of the EQE spectrum in the second infrared wavelength region may be at least partially defined by a distance between the reflective layer and the second electrode, and the distance between the reflective layer and the second electrode may be at least partially defined by at least one of a thickness of the light absorbing layer or a thickness of the buffer layer.

In some embodiments, as the distance between the reflective layer and the second electrode increases, the peak wavelength of the EQE spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a wavelength magnitude of the peak wavelength of the EQE spectrum in the second infrared wavelength region is proportional to the distance between the reflective layer and the second electrode.

In some embodiments, as the thickness of the light absorbing layer increases, the peak wavelength of the EQE spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a wavelength magnitude of the peak wavelength of the EQE spectrum in the second infrared wavelength region is proportional to the thickness of the light absorbing layer.

In some embodiments, as the thickness of the buffer layer increases, the peak wavelength of the EQE spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a wavelength magnitude of the peak wavelength of the EQE spectrum in the second infrared wavelength region is proportional to the thickness of the buffer layer.

In some embodiments, the light absorbing layer may include a near-infrared absorbing material, and a counter material defining a pn junction with the near-infrared absorbing material. The near-infrared absorbing material may be configured to absorb light in both the first absorption spectrum and the second absorption spectrum. A peak wavelength of the EQE spectrum in the second infrared wavelength region may be at least partially defined by a composition ratio of the near-infrared absorbing material and the counter material in the light absorbing layer.

In some embodiments, as the composition ratio of the near-infrared absorbing material relative to the counter material is higher, the peak wavelength of the EQE spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a magnitude of the peak wavelength of the EQE spectrum in the second infrared wavelength region is proportional to the composition ratio of the near-infrared absorbing material relative to the counter material.

In some embodiments, the reflective layer may include Ag, Cu, Al, Au, Ti, Cr, Ni, an alloy thereof, a nitride thereof, or any combination thereof.

In some embodiments, the second electrode may include a semi-transmissive layer.

In some embodiments, the first electrode and the second electrode may be configured to collectively define a microcavity in the sensor, and a peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be at least partially defined by a resonance wavelength of the microcavity.

In some embodiments, the sensor may further include an optical auxiliary layer on the second electrode, wherein the second electrode includes a light-transmitting layer, a semi-transmissive layer, or any combination thereof.

In some embodiments, the optical auxiliary layer may include a first optical auxiliary layer and a second optical auxiliary layer, the first optical auxiliary layer and the second optical auxiliary layer having different refractive indexes.

In some embodiments, the first electrode and the second electrode, or the first electrode and the optical auxiliary layer, may collectively define a microcavity, and a peak wavelength of the EQE spectrum in the second infrared wavelength region may be at least partially defined by a resonance wavelength of the microcavity.

In some embodiments, the second electrode may include an inorganic nano-layer facing the light absorbing layer such that the inorganic nano-layer is proximate to the light absorbing layer in relation to a surface of the second electrode that is distal from the light absorbing layer, and the inorganic nano-layer may include ytterbium (Yb), calcium (Ca), potassium (K), barium (Ba), magnesium (Mg), lithium fluoride (LiF), or an alloy thereof.

In some embodiments, the sensor may further include a semiconductor substrate, the semiconductor substrate being under the first electrode.

In some embodiments, an electronic device may include the sensor.

Hereinafter, example embodiments will be described in detail so that a person skilled in the art would understand the same. This disclosure may, however, be embodied in many different forms and is not construed as limited to the example embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present such that the element and the other element are isolated from direct contact with each other by one or more interposing spaces and/or structures. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present such that the element and the other element are in direct contact with each other. As described herein, an element that is "on" another element may be above, beneath, and/or horizontally adjacent to the other element.

As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one," unless the content clearly indicates otherwise.

It will be understood that elements and/or properties thereof may be recited herein as being "the same" or "equal" as other elements, and it will be further understood that elements and/or properties thereof recited herein as being "the same" as or "equal" to other elements may be "the same" as or "equal" to or "substantially the same" as or "substantially equal" to the other elements and/or properties thereof. Elements and/or properties thereof that are "substantially the same" as or "substantially equal" to other elements and/or properties thereof will be understood to include elements and/or properties thereof that are the same as or equal to the other elements and/or properties thereof within manufacturing tolerances and/or material tolerances. Elements and/or properties thereof that are the same or substantially the same as other elements and/or properties thereof may be structurally the same or substantially the same, functionally the same or substantially the same, and/or compositionally the same or substantially the same.

It will be understood that elements and/or properties thereof described herein as being the "substantially" the same encompasses elements and/or properties thereof that have a relative difference in magnitude that is equal to or less than <NUM>%. Further, regardless of whether elements and/or properties thereof are modified as "substantially," it will be understood that these elements and/or properties thereof should be construed as including a manufacturing or operational tolerance (e.g., ±<NUM>%) around the stated elements and/or properties thereof.

Hereinafter, a sensor according to some example embodiments is described.

A sensor according to some example embodiments (hereinafter, referred to as an "infrared sensor") is configured to sense light in an infrared wavelength region. The infrared sensor is configured to sense light in at least a portion of the infrared wavelength region. The infrared wavelength region may, for example, belong to a wavelength region (also referred to herein interchangeably as being within a wavelength region) of greater than about <NUM> and less than or equal to <NUM>, for example from about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. A wavelength region" as described herein may be interchangeably referred to as a "wavelength spectrum.

<FIG> is a cross-sectional view showing an example of an infrared sensor according to some example embodiments, and <FIG> is an optical spectrum of an example of the infrared sensor of <FIG>.

Referring to <FIG>, an infrared sensor <NUM> according to some example embodiments includes a first electrode <NUM>, a second electrode <NUM>, a light absorbing layer <NUM> between the first electrode <NUM> and the second electrode <NUM>, and buffer layers <NUM> and <NUM>. It will be understood that in some example embodiments one or both of the buffer layers <NUM> and <NUM> may be omitted from infrared sensor <NUM>.

A substrate <NUM> may be disposed under the first electrode <NUM> or may be disposed on (e.g., above) the second electrode <NUM>. For example, the substrate <NUM> may be disposed under the first electrode <NUM>. The substrate <NUM> may include, for example, a semiconductor substrate such as silicon substrate; a glass substrate; or a polymer substrate such as polycarbonate, polymethylmethacrylate, polyethyleneterephthalate, polyethylenenaphthalate, polyamide, polyethersulfone, or any combination thereof, but is not limited thereto. The substrate <NUM> may be omitted from infrared sensor <NUM>.

One of the first electrode <NUM> and the second electrode <NUM> is an anode, and the other is a cathode. For example, the first electrode <NUM> may be an anode and the second electrode <NUM> may be a cathode. For example, the first electrode <NUM> may be a cathode and the second electrode <NUM> may be an anode.

The first electrode <NUM> may be a reflective electrode including a reflective layer.

For example, the first electrode <NUM> may be formed of (e.g., may at least partially or completely comprise) a reflective layer including an optically opaque material. The reflective layer may, for example, have a light transmittance of less than about <NUM>%, for example, a light transmittance of less than or equal to about <NUM>%, less than or equal to about <NUM>%, less than or equal to about <NUM>%, less than or equal to about <NUM>%, or less than or equal to about <NUM>%. The light transmittance of the reflective layer may, in addition to being equal to or less than at least one of the aforementioned transmittance values, be greater than or equal to <NUM>%, for example greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, or greater than or equal to about <NUM>%. The reflective layer may have (e.g., may include), for example, a reflectance of greater than or equal to about <NUM>%, for example, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, or greater than or equal to about <NUM>%. The reflectance of the reflective layer may, in addition to being greater than or equal to at least one of the aforementioned reflectance values, be equal to or less than <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, or equal to or less than about <NUM>%. The optically opaque material may include a metal, a metal nitride, or any combination thereof, for example silver (Ag), copper (Cu), aluminum (Al), gold (Au), titanium (Ti), chromium (Cr), Nickel (Ni), an alloy thereof, a nitride thereof (e.g., TiN), or any combination thereof, but is not limited thereto. The reflective layer may be one layer or two or more layers.

For example, the first electrode <NUM> may include a reflective layer including an optically opaque material and a light-transmitting layer including an optically transparent material. The reflective layer is as described above. The light-transmitting layer may have a high transmittance of greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, or greater than or equal to about <NUM>%, and may include an optically transparent conductor. The light transmittance of the light transmitting layer may, in addition to being greater than or equal to at least one of the aforementioned transmittance values, be equal to or less than <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, equal to or less than about <NUM>%, or equal to or less than about <NUM>%. The light-transmitting layer may include at least one of an oxide conductor, a carbon conductor, and/or a metal thin film. The oxide conductor may include, for example, one or more selected from indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), aluminum tin oxide (ATO), and/or aluminum zinc oxide (AZO). The carbon conductor may be one or more selected from graphene and/or carbon nano-bodies. The metal thin film may be, for example, a metal thin film with a thin thickness of several nanometers to tens of nanometers, or a single layer or multiple layers doped with metal oxide with a thin thickness of several nanometers to several tens of nanometers.

For example, the first electrode <NUM> may be formed of (e.g., at least partially or completely comprise) a reflective layer or may be a stacked structure of a reflective layer/light-transmitting layer or a light-transmitting layer/reflective layer/light-transmitting layer.

The second electrode <NUM> may include (e.g., may at least partially or completely comprise) a semi-transmissive layer. The semi-transmissive layer may have a light transmittance between the light-transmitting layer and the reflective layer, and may have a light transmittance of about <NUM>% to about <NUM>%, about <NUM>% to about <NUM>%, or about <NUM>% to about <NUM>%. The semi-transmissive layer, for example, may be configured to selectively transmit light in a particular (or, alternatively, predetermined) wavelength region and reflect or absorb light in other wavelength regions. The semi-transmissive layer may include, for example, a thin metal layer or an alloy layer of about <NUM> to about <NUM> and may include, for example, silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), magnesium-silver (Mg-Ag), magnesium-aluminum (Mg-Al), or any combination thereof, but is not limited thereto.

For example, the second electrode <NUM> may further include an inorganic nano-layer in addition to the semi-transmissive layer. The inorganic nano-layer may be disposed facing the light absorbing layer <NUM> (e.g., in direct contact with the light absorbing layer <NUM> and/or proximate to the light absorbing layer <NUM> in relation to a surface of the second electrode <NUM> that is distal from the light absorbing layer <NUM>), for example, may be formed under the semi-transmissive layer in a thin thickness (e.g., between the semi-transmissive layer and the light absorbing layer <NUM>). For example, the inorganic nano-layer may be in contact (e.g., direct contact) with the semi-transmissive layer. The inorganic nano-layer may be a very thin film of several nanometers in thickness, for example, may have a thickness of less than or equal to about <NUM>, for example less than or equal to about <NUM>, or less than or equal to about <NUM>. The inorganic nano-layer may have, for example, a thickness of greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, or greater than or equal to about <NUM>. The inorganic nano-layer may have, for example, a thickness of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. The inorganic nano-layer may include an inorganic material having a shallower work function than the semi-transmissive layer, for example, a lanthanide element such as ytterbium (Yb); calcium (Ca); potassium (K); barium (Ba); magnesium (Mg); lithium fluoride (LiF); or an alloy thereof. An effective work function of the surface of the second electrode <NUM> facing the light absorbing layer <NUM> may be lowered due to the inorganic nano-layer, and thus facilitate extraction of charge carriers (for example, electrons) moving from the light absorbing layer <NUM> to the second electrode <NUM>, thereby reducing remaining charge carriers at the interface of the second electrode <NUM> and the light absorbing layer <NUM> and improving charge extraction efficiency.

The light absorbing layer <NUM> includes (e.g., at least partially or completely comprises) a near-infrared absorbing material configured to absorb light in a portion (e.g., some or all) of the infrared wavelength region. The near-infrared absorbing material may be an organic material, an inorganic material, an organic-inorganic material, or any combination thereof. For example, the near-infrared absorbing material may be an organic material, for example, a non-polymer or a polymer, for example, a low-molecular weight compound that may be deposited.

The near-infrared absorbing material may include for example a quantum dot, a polymethine compound, a cyanine compound, a phthalocyanine compound, a merocyanine compound, a naphthalocyanine compound, an immonium compound, a diimmonium compound, a triarylmethane compound, a dipyrromethene compound, an anthraquinone compound, a diquinone compound, a naphthoquinone compound, a squarylium compound, a rylene compound, a perylene compound, a pyrylium compound, a squaraine compound, a thiopyrylium compound, a diketopyrrolopyrrole) compound, a boron-dipyrromethene compound, a nickel-dithiol complex compound, a croconium compound, a derivative thereof, or a combination thereof, but is not limited thereto.

The near-infrared absorbing material may include a compound represented by Chemical Formula <NUM>.

The absorption spectrum in the infrared wavelength region of the light absorbing layer <NUM> may be substantially the same as the absorption spectrum of the near-infrared absorbing material.

Referring to <FIG>, the absorption spectrum in the infrared wavelength region of the light absorbing layer <NUM> may have at least two peaks, for example, a first absorption spectrum (P1) having a main absorption peak (e.g., a main absorption peak, also referred to as a first absorption peak and/or a first peak absorption intensity) in a relatively short wavelength region (hereinafter referred to as "a first infrared wavelength region (A1)") of the infrared wavelength region and a second absorption spectrum (P2) having a sub-absorption peak (e.g., a sub-absorption peak, also referred to as a second absorption peak and/or a second peak absorption intensity) in a region (hereinafter referred to as "a second infrared wavelength region (A2)") having a longer wavelength than that of the first infrared wavelength region. An absorption peak at a particular wavelength may be referred to as a peak absorption intensity at said particular wavelength. The second absorption spectrum (P2) and the first absorption spectrum (P1) may be understood to be separate from each other (e.g., may not at least partially overlap with each other), such that there is no wavelength that is included in both the first absorption spectrum (P1) and the second absorption spectrum (P2) and a shortest wavelength in the second absorption spectrum P2 may be longer than a longest wavelength in the first absorption spectrum P1, such that the second infrared wavelength region A2 may be understood to be a region having a longer wavelength than that of the first infrared wavelength region A1. The second infrared wavelength region A2 may include longer wavelengths than the first infrared wavelength region A1 and may not at least partially overlap with the first infrared wavelength region A1, for example a shortest wavelength in the second infrared wavelength region A2 may be longer than a longest wavelength in the first infrared wavelength region A1, such that the second infrared wavelength region A2 may be understood to be a region having a longer wavelength than that of the first infrared wavelength region A1. A height (e.g., magnitude, intensity, etc.) of the sub-absorption peak may be lower than a height (e.g., magnitude, intensity, etc.) of the main absorption peak.

The first absorption spectrum (P1) may be a main absorption spectrum of the near-infrared absorbing material, and a wavelength (λ<NUM>) at the absorption peak of the first absorption spectrum (P1) (e.g., a wavelength of the first peak absorption intensity) may be a maximum absorption wavelength (λmax) of the near-infrared absorbing material and thus may be a maximum absorption wavelength of the infrared sensor <NUM>, which may be within a range of about <NUM> to about <NUM>. Accordingly, it will be understood that a light absorbing layer <NUM> including the near-infrared absorbing material may have a maximum absorption wavelength (e.g., a wavelength of incident light at which the light absorbing layer <NUM> exhibits maximum absorption) that is within a range of about <NUM> to about <NUM>. The near-infrared absorbing material may be considered to be configured to absorb light in both the first absorption spectrum (P1) and the second absorption spectrum (P2). The wavelength (λ<NUM>) at the absorption peak of the first absorption spectrum (P1) (e.g., the wavelength at the first absorption peak, which may be referred to as a first absorption peak wavelength, a wavelength of the first peak absorption intensity, or the like) may be, for example, greater than about <NUM> and less than about <NUM> (e.g., a wavelength within a range, also referred to herein as a wavelength spectrum, of about <NUM> to about <NUM>), within the range, greater than about <NUM> and less than or equal to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

The second absorption spectrum (P2) may be a sub-absorption spectrum having a lower absorption intensity than the first absorption spectrum (P1), and the wavelength (λ<NUM>) at the absorption peak of the second absorption spectrum (P2) (e.g., the wavelength at the second absorption peak, which may be referred to as a second absorption peak wavelength, a wavelength of the second peak absorption intensity, or the like) may be a longer wavelength than the wavelength (λ<NUM>) at the absorption peak of the first absorption spectrum (P1) (e.g., the first absorption peak wavelength). For example, a difference between the wavelength (λ<NUM>) at the absorption peak of the second absorption spectrum (P2) and the wavelength (λ<NUM>) at the absorption peak of the first absorption spectrum (P1) may be greater than or equal to about <NUM>, for example greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM> or greater than or equal to about <NUM>, for example equal to or less than about <NUM>, for example about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

For example, the wavelength (λ<NUM>) at the absorption peak of the second absorption spectrum (P2) may be about <NUM> to about <NUM>, within the range, for example about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

It will be understood that where a wavelength, intensity, property, or the like is referred to as being "about" a first value to a second value, said wavelength, intensity, property, or the like may be interchangeably referred to herein as being within a range of about the first value to about the second value.

An absorption intensity (Abs<NUM>) at the absorption peak of the first absorption spectrum (P1), also referred to herein as a first absorption intensity, may be greater than an absorption intensity (Abs<NUM>) at the absorption peak of the second absorption spectrum (P2), also referred to herein as a second absorption intensity, and may, for example, satisfy Relationship Equation <NUM>.

For example, Relationship Equation <NUM> may satisfy Relationship Equation 1a.

As an example, Relationship Equation <NUM> may satisfy Relationship Equation 1b.

As an example, Relationship Equation <NUM> may satisfy Relationship Equation 1c.

As an example, Relationship Equation <NUM> may satisfy Relationship Equation 1d.

In some example embodiments, the wavelength having the lowest reflectance in a reflection spectrum in an infrared wavelength region of the light absorbing layer <NUM> is the same as the wavelength (λ<NUM>) in the absorption peak of the second absorption spectrum or may be within ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, or ±<NUM>.

The light absorbing layer <NUM> is a photoelectric conversion layer configured to convert absorbed light into an electrical signal. The light absorbing layer <NUM> may be configured to generate a current in a particular (or, alternatively, predetermined) wavelength region based on the aforementioned absorption characteristics. This will be described later.

The light absorbing layer <NUM> may form a pn junction for photoelectric conversion, and the aforementioned near-infrared absorbing material may be a p-type semiconductor or an n-type semiconductor. The light absorbing layer <NUM> may further include a counter material for forming a pn junction with the near-infrared absorbing material. Restated, the light absorbing layer <NUM> as shown in <FIG> may include a near-infrared absorbing material and a counter material that forms (e.g., defines) a pn junction with the near-infrared absorbing material (e.g., the light absorbing layer <NUM> may include a mixture or stack of layers including the near-infrared absorbing material and the counter material that collectively define a pn junction. For example, when the near-infrared absorbing material is a p-type semiconductor, the counter material may be an n-type semiconductor. For example, when the near-infrared absorbing material is an n-type semiconductor, the counter material may be a p-type semiconductor. The counter material may be, for example, an organic material, an inorganic material, or an organic-inorganic material. The counter material may be a light absorbing material or a non-light absorbing material.

In some example embodiments, the light absorbing layer <NUM> may include a near-infrared absorbing material that is a p-type semiconductor, such as Sn naphthaloxyanine and/or Sn naphthalocyanine, and a counter material (B) that is an n-type semiconductor, such as C60.

The light absorbing layer <NUM> may include a mixed layer in which the near-infrared absorbing material and the counter material are mixed in a bulk heterojunction form. The mixed layer may include the near-infrared absorbing material and the counter material in a particular (or, alternatively, predetermined) composition ratio, where the composition ratio may be defined as a volume or thickness of the near-infrared absorbing material relative to a volume or thickness of the counter material.

For example, the near-infrared absorbing material may be included in the light absorbing layer <NUM> in an amount that is less than or equal to that of the counter material in the light absorbing layer <NUM>, for example, the composition ratio of the near-infrared absorbing material relative to the counter material may be about <NUM> to about <NUM>. The composition ratio of the near-infrared absorbing material relative to the counter material may be about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

The light absorbing layer <NUM> may have a thickness of about <NUM> to about <NUM>, and may have a thickness of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or <NUM> to about <NUM>.

The buffer layers <NUM> and <NUM> include at least one first buffer layer <NUM> between the first electrode <NUM> and the light absorbing layer <NUM> and at least one second buffer layer <NUM> between the second electrode <NUM> and the light absorbing layer <NUM>. Each of the first buffer layer <NUM> and the second buffer layer <NUM> may be independently a charge auxiliary layer configured to control mobility of holes and/or electrons separated from the light absorbing layer <NUM> or a light absorbing auxiliary layer to improve light absorption characteristics. For example, the first buffer layer <NUM> and the second buffer layer <NUM> may include one or more selected from a hole injecting layer (HIL), a hole transporting layer (HTL), an electron blocking layer (EBL), an electron injecting layer (EIL), an electron transporting layer (ETL), a hole blocking layer (HBL), and a light absorbing auxiliary layer. The first buffer layer <NUM> and the second buffer layer <NUM> may independently include an organic material, an inorganic material, an organic-inorganic material, or a combination thereof (e.g., a triphenylamine derivative).

The buffer layers <NUM> and <NUM> may have independently a thickness of about <NUM> to about <NUM>, within the range, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. At least one of the first buffer layer <NUM> or the second buffer layer <NUM> may be omitted.

The infrared sensor <NUM> may further include an anti-reflection layer (not shown) and/or an encapsulant (not shown) disposed on the second electrode <NUM>.

As described above, the infrared sensor <NUM> includes a first electrode <NUM> including a reflective layer, a second electrode <NUM> including a semi-transmissive layer, and a light absorbing layer <NUM> and buffer layers <NUM> and <NUM> therebetween, and thus a microcavity structure (also referred to herein as simply a "microcavity") may be formed. Restated, the first electrode <NUM> and the second electrode <NUM> may be configured to collectively define a microcavity in the infrared sensor <NUM>. Due to the microcavity structure, incident light may be configured to be repeatedly reflected between the reflective layer and the semi-transmissive layer which are separated by a particular (or, alternatively, predetermined) distance (namely, optical path length) to enhance light of a particular (or, alternatively, predetermined) wavelength spectrum. For example, light of a particular (or, alternatively, predetermined) wavelength spectrum among the incident light may be modified by repeatedly reflecting between the reflective layer and the semi-transmissive layer, and among the modified light, light of a wavelength spectrum corresponding to a resonance wavelength of the microcavity may be enhanced to exhibit amplified photoelectric conversion characteristics in a narrow wavelength region.

As described above, the absorption spectrum of the light absorbing layer <NUM> is the first absorption spectrum (P1) having a main absorption peak in the first infrared wavelength region (A1), which is a region of the infrared wavelength region having a relatively short wavelength and a second absorption spectrum (P2) having a sub-absorption peak in the second infrared wavelength region (A2), which is a region having a longer wavelength than that of the first infrared wavelength region (A1).

Based on such optical properties of the light absorbing layer <NUM>, a microcavity structure may be formed to have amplified photoelectric conversion characteristics in the second infrared wavelength region (A2) having the sub- absorption peak. Accordingly, the infrared sensor <NUM> includes a near-infrared absorbing material having the main absorption peak in the relatively short wavelength region of less than about <NUM> and may be configured to photoelectrically convert and effectively sense light of the infrared wavelength spectrum in the relatively long wavelength region of greater than or equal to about <NUM>, for example, greater than or equal to about <NUM>. Accordingly, the infrared sensor <NUM> may overcome a limit of the absorption wavelength of the near-infrared absorbing material and be realized with a desired target wavelength and effectively used, such that light-sensing performance of the infrared sensor <NUM> is improved.

The photoelectric conversion characteristics of the infrared sensor <NUM> may be expressed to photoelectric conversion efficiency, and the photoelectric conversion efficiency may be in general evaluated from external quantum efficiency (EQE). The external quantum efficiency (EQE) may be a ratio of extracted charges relative to incident photons. In other words, high EQE regarding a particular (or, alternatively, predetermined) wavelength region (e.g., a local peak EQE within the particular wavelength region) may mean that the infrared sensor <NUM> may have high photoelectric conversion characteristics in the particular (or, alternatively, predetermined) wavelength region and be configured to effectively generate a current.

<FIG> is an EQE spectrum of an example of the infrared sensor of <FIG>, according to some example embodiments. Referring to <FIG>, the infrared sensor <NUM> has amplified photoelectric conversion characteristics in the second infrared wavelength region (A2) having the sub-absorption peak and thus may exhibit an amplified EQE spectrum in the second infrared wavelength region (A2). Herein, "amplified" may mean that since EQE is greatly increased compared with absorption intensity of the absorption spectrum in the corresponding wavelength region, and a full width at half maximum (FWHM) of the EQE spectrum is greatly narrowed compared with a full width at half maximum (FWHM) of the absorption spectrum in the corresponding wavelength region, detection selectivity is thus increased. The full width at half maximum (FWHM) of the absorption spectrum may be a width of a wavelength corresponding to a half of the absorption peak, and the full width at half maximum (FWHM) of the EQE spectrum may be a width of a wavelength corresponding to a half of an EQE maximum value in the EQE spectrum. For example, the amplified EQE spectrum in the microcavity structure may be confirmed by comparing with the EQE spectrum in the infrared sensor that does not form the microcavity structure.

When the external quantum efficiency (EQE) spectrum in the second infrared wavelength region A2 is amplified, and as shown in <FIG>, the EQE may exhibit a local peak value (e.g., peak wavelength of the EQE spectrum) in the second infrared wavelength region that has a greater variance from the rest of (e.g., a remainder of) the EQE values of the EQE spectrum in the second infrared wavelength region A2 than the variance of the absorption peak value of the second absorption spectrum P2 from the rest values (e.g., absorption intensities) of the second absorption spectrum P2 in the second infrared wavelength region A2 and/or the full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region A2 may be narrower than the full width at half maximum (FWHM) of the second absorption spectrum P2 in the second infrared wavelength region A2. For example, the variance of the peak wavelength of the EQE spectrum from the rest EQE values of the EQE spectrum in the second infrared wavelength region A2 may be greater than or equal to about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or greater than <NUM>% of the variance of the peak of the absorption peak of the second absorption spectrum P2 from the rest values of the of the second absorption spectrum P2 in the second infrared wavelength region A2. In another example, the full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region A2 is less than or equal to <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, and/or <NUM>%, and/or greater than <NUM>%, of the full width at half maximum (FWHM) of the second absorption spectrum P2 in the second infrared wavelength region A2.

Accordingly, it will be understood that an external quantum efficiency (EQE) spectrum in the second infrared wavelength region A2 may be amplified, such that a variance of a maximum EQE value (EQEmax) (e.g., local maximum EQE value) at a peak wavelength of the EQE spectrum from a remainder of EQE values of the EQE spectrum in the second infrared wavelength region A2 is greater than a variance of the second absorption peak at the wavelength (λ<NUM>) from absorption values at a remainder of absorption intensities of the second absorption spectrum P2 in the second infrared wavelength region A2, and/or a full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region A2 is smaller (e.g., narrower) than a full width at half maximum (FWHM) of the second absorption spectrum P2 in the second infrared wavelength region A2.

As shown in <FIG>, the amplified EQE spectrum may be characterized in that, when a maximum absorption wavelength of the infrared sensor <NUM> is within a range of about <NUM> to about <NUM>, the EQE spectrum of the infrared sensor <NUM> has a local maximum EQE value (EQEmax) at a local peak wavelength (λpeak,EQE) that is greater than about <NUM>, such that EQE values of the EQE spectrum of the infrared sensor <NUM> at all wavelengths up to <NUM> shorter than the local peak wavelength are smaller than the local maximum EQE value (EQEmax), and EQE values of the EQE spectrum of the infrared sensor <NUM> at all wavelengths up to <NUM> longer than the local peak wavelength (λpeak,EQE) are smaller than the local maximum EQE value (EQEmax). For example, even if EQE values of the EQE spectrum of the infrared sensor <NUM> at wavelengths shorter than about <NUM> are greater than EQE values of the EQE spectrum of the infrared sensor <NUM> at wavelengths longer than about <NUM>, it may include a localized peak EQE value having a local maximum EQE value (EQEmax) (e.g., at about <NUM>) that is greater than all other EQE values within <NUM> of the wavelength at which the local maximum EQE value (EQEmax) exists in the EQE spectrum of the infrared sensor <NUM> (e.g., all other EQE values at about <NUM> to about <NUM> and about <NUM> to about <NUM>).

For example, an EQE maximum value (EQEmax) (e.g., peak EQE value, EQE value at peak wavelength of the EQE spectrum, local maximum EQE value, etc.) in the second infrared wavelength region (A2) of the infrared sensor <NUM> (e.g., a wavelength region of greater than or equal to about <NUM>, about <NUM> to about <NUM>, etc.) may be greater than or equal to about <NUM>%, within the range, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, or greater than or equal to about <NUM>%. The EQE maximum value (EQEmax) in the second infrared wavelength region (A2) of the infrared sensor <NUM> may be less than or equal to <NUM>%, less than or equal to about <NUM>%, less than or equal to about <NUM>%, or less than or equal to about <NUM>%.

For example, the full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region (A2) of the infrared sensor <NUM> may be narrower (e.g., smaller) than the full width at half maximum (FWHM) of the EQE spectrum in the first infrared wavelength region (A1). For example, the full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region (A2) of the infrared sensor <NUM> may be less than or equal to about <NUM>, within the range, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, less than or equal to about <NUM>, or less than or equal to about <NUM>. The full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region (A2) of the infrared sensor <NUM> may, in addition to being less than or equal to any of the aforementioned values, be greater than or equal to about <NUM>. The full width at half maximum (FWHM) of the EQE spectrum in the second infrared wavelength region (A2) of the infrared sensor <NUM> may be about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

The infrared sensor <NUM> may obtain an amplified EQE spectrum having a peak wavelength (λpeak,EQE) belonging to (also referred to herein interchangeably as being within) the second infrared wavelength region (A2) by adjusting a resonance wavelength of the microcavity structure. It will be understood that the peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may be referred to as a local peak wavelength of the EQE spectrum (e.g., a local peak wavelength of the EQE spectrum in the second infrared wavelength region) and the EQE value at the local peak wavelength may be referred to as a local maximum EQE value of the EQE spectrum (e.g., a local maximum EQE value of the EQE spectrum in the second infrared wavelength region. For example, the peak wavelength (λpeak,EQE) belonging to the second infrared wavelength region (A2) may correspond to (e.g., may be at least partially defined by) a resonance wavelength of the microcavity structure. For example, the peak wavelength (λpeak,EQE) belonging to the second infrared wavelength region (A2) may be the same as the wavelength at the absorption peak in the absorption spectrum or the wavelength showing the lowest reflectivity in the reflection spectrum or may be within ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, ±<NUM>, or ±<NUM>. The peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may in a range between, for example, about <NUM> to about <NUM>, within the range, for example about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

The peak wavelength (λpeak,EQE) of the EQE spectrum may be controlled by various factors, such as an optical path length, which is a distance between the reflective layer and the semi-transmissive layer (e.g., a distance between the reflective layer and the second electrode <NUM>), and/or optical properties between the reflective layer and the semi-transmissive layer. Restated, the peak wavelength (λpeak,EQE) of the EQE spectrum may be at least partially defined by (e.g., determined by) an optical path length, which is a distance between the reflective layer and the semi-transmissive layer (e.g., a distance between the reflective layer and the second electrode <NUM>).

For example, the peak wavelength (λpeak,EQE) of the EQE spectrum of the infrared sensor <NUM> may be determined by an optical length, which is a distance between the reflective layer and the semi-transmissive layer, and as the optical length is larger, the peak wavelength (λpeak,EQE) of the EQE spectrum may be shifted toward the longer wavelength region. For example, as the distance between the reflective layer and the second electrode <NUM> increases, the peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a wavelength magnitude of the peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be proportional (e.g., directly proportional) to the distance between the reflective layer and the second electrode <NUM>.

For example, in the infrared sensor <NUM> of <FIG>, the peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may be controlled by (e.g., at least partially defined by) at least one of a thickness of the light absorbing layer <NUM> or a thickness of one or more of the buffer layers <NUM> and/or <NUM>.

For example, in the second infrared wavelength region (A2), the peak wavelength (λpeak,EQE) of the EQE spectrum may be controlled by the thickness of the light absorbing layer <NUM>. For example, as the thickness of the light absorbing layer <NUM> is thicker, the peak wavelength of the EQE spectrum in the second infrared wavelength region (A2) may be shifted toward the longer wavelength region. For example, as the thickness of the light absorbing layer <NUM> increases, the peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a wavelength magnitude of the peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be proportional (e.g., directly proportional) to the thickness of the light absorbing layer <NUM>.

For example, in the second infrared wavelength region (A2), the peak wavelength (λpeak,EQE) of the EQE spectrum may be controlled by the thicknesses of the buffer layers <NUM> and <NUM>. For example, as the thicknesses of the buffer layers <NUM> and <NUM> are thicker, the peak wavelength of the EQE spectrum in the second infrared wavelength region (A2) may be shifted toward the longer wavelength region.

For example, in the second infrared wavelength region (A2), the peak wavelength (λpeak,EQE) of the EQE spectrum may be controlled by a thickness sum of the light absorbing layer <NUM> and the buffer layers <NUM> and <NUM>. For example, as the thickness sum of the light absorbing layer <NUM> and the buffer layers <NUM> and <NUM> is larger, the peak wavelength of the EQE spectrum in the second infrared wavelength region (A2) may be shifted toward the longer wavelength region. In another example, as the thickness at least one of the buffer layers <NUM> and/or <NUM> increases, the peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be shifted to a longer wavelength region, such that a wavelength magnitude of the peak wavelength of the external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be proportional (e.g., directly proportional) to the thickness of the at least one buffer layer <NUM> and/or <NUM>.

For example, the peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may be controlled by an absorption coefficient of the near-infrared absorbing material included in the light absorbing layer <NUM>. For example, as the absorption coefficient of the near-infrared absorbing material is higher, the peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may be shifted toward the longer wavelength region.

For example, the peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may be controlled by (e.g., at least partially defined by) a composition ratio (a volume ratio or a thickness ratio) of the near-infrared absorbing material and the counter material included in the light absorbing layer <NUM>. For example, as the composition ratio (the volume ratio or the thickness ratio) of the near-infrared absorbing material relative to the counter material is higher, the peak wavelength (λpeak,EQE) of the EQE spectrum in the second infrared wavelength region (A2) may be shifted toward the longer wavelength region. Restated, a magnitude of the peak wavelength of the EQE spectrum in the second infrared wavelength region may be proportional (e.g., directly proportional) to the composition ratio of the near-infrared absorbing material relative to the counter material.

In this way, the infrared sensor <NUM> according to some example embodiments has a structure capable of selecting and controlling a target wavelength for photoelectric conversion in the infrared wavelength region and may be realized and effectively used depending on the desired target wavelength. Particularly, like a wavelength region of greater than or equal to about <NUM> (e.g., about <NUM> to about <NUM>), for example, greater than or equal to about <NUM> (e.g., about <NUM> to about <NUM>), or for example, greater than or equal to about <NUM> (e.g., about <NUM> to about <NUM>), even when the target wavelength belongs to the long wavelength region not sensible in a silicon photodiode, the light of the target wavelength may be effectively photoelectrically converted and thus a usable range of the infrared sensor <NUM> may be broadened. Accordingly, the infrared sensor <NUM> may be configured to generate current (e.g., electrical current) based on photoelectrically converting light (e.g., incident light) in a wavelength region of greater than or equal to about <NUM> (e.g., about <NUM> to about <NUM>).

<FIG> is a cross-sectional view showing another example of a sensor according to some example embodiments, and <FIG> is a cross-sectional view showing an example of the optical auxiliary layer in the sensor of <FIG>.

Referring to <FIG>, the infrared sensor <NUM> according to some example embodiments includes a first electrode <NUM>, a second electrode <NUM>, and a light absorbing layer <NUM> between the first electrode <NUM> and the second electrode <NUM>, and buffer layers <NUM> and <NUM>, as in some example embodiments, including the example embodiments shown in at least <FIG>.

However, the infrared sensor <NUM> according to some example embodiments, including the example embodiments shown in <FIG> may further include an optical auxiliary layer <NUM>, unlike some example embodiments, including the example embodiments shown in at least <FIG>. The second electrode <NUM> as shown in <FIG> may include a semi-transmissive layer, a light-transmitting layer, or any combination thereof.

The optical auxiliary layer <NUM> may be configured to selectively transmit light in a particular (or, alternatively, predetermined) wavelength region among incident light and reflect and/or absorb light in other wavelength regions. That is, the optical auxiliary layer <NUM> may be a selective transmission layer, for example, a semi-transmissive layer.

Referring to <FIG>, the optical auxiliary layer <NUM> may include a first optical auxiliary layer 160a and a second optical auxiliary layer 160b having different refractive indexes. Either one of the first optical auxiliary layer 160a or the second optical auxiliary layer 160b may be a high refractive index layer and have a refractive index of greater than or equal to about <NUM>, for example, about <NUM> to about <NUM> in the infrared wavelength region. The other one of the first optical auxiliary layer 160a or the second optical auxiliary layer 160b may be a low refractive index layer and have a refractive index of less than about <NUM>, for example, greater than or equal to about <NUM> and less than about <NUM> in the infrared wavelength region. For example, the first optical auxiliary layer 160a may be aluminum oxide, an organic buffer material, an inorganic buffer material, or any combination thereof, and the second optical auxiliary layer 160b may be silicon oxide, silicon nitride, silicon oxynitride, or any combination thereof, but are not limited thereto.

A thickness of the second optical auxiliary layer 160b may be greater than or equal to that of the first optical auxiliary layer 160a, for example, about <NUM> times to about <NUM> times greater than that of the first optical auxiliary layer 160a and within the range, about <NUM> times to about <NUM> times, about twice to about <NUM> times, or about <NUM> times to about <NUM> times greater than that of the first optical auxiliary layer 160a.

The optical auxiliary layer <NUM> may further include an additional layer (not shown) in addition to the first optical auxiliary layer 160a and the second optical auxiliary layer 160b.

The optical auxiliary layer <NUM> is a semi-transmissive layer, and unlike some example embodiments, including the example embodiments shown in at least <FIG>, the second electrode <NUM> may not include a separate semi-transmissive layer. In other words, the second electrode <NUM> may be selected from a light-transmitting layer, a semi-transmissive layer, or any combination thereof. For example, the second electrode <NUM> and the optical auxiliary layer <NUM> may be semi-transmissive layers, respectively. For example, the second electrode <NUM> may be a light-transmitting layer and the optical auxiliary layer <NUM> may be a semi-transmissive layer.

The light-transmitting layer may have a high transmittance of equal to or less than <NUM>% and greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, greater than or equal to about <NUM>%, or greater than or equal to about <NUM>%, and may include an optically transparent conductor. The light-transmitting layer may include, for example, at least one of an oxide conductor such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), aluminum tin oxide (ATO), and aluminum zinc oxide (AZO); a carbon conductor such as graphene and a carbon nanostructure; and/or a metal thin film having a thin thickness of several nanometers to tens of nanometers, or a single layer or multiple layers doped a metal oxide having a thin thickness of several nanometers to several tens of nanometers.

The infrared sensor <NUM> according to some example embodiments includes the first electrode <NUM> including a reflective layer, the second electrode <NUM> including a semi-transmissive layer and/or the optical auxiliary layer <NUM>, and the light absorbing layer <NUM> and the buffer layers <NUM> and <NUM> disposed therebetween and thus may form (e.g., collectively define) the microcavity structure and, as described above, intensify light of a wavelength spectrum corresponding to a resonance wavelength of microcavity to exhibit amplified photoelectric conversion characteristics in the narrow wavelength region. For example, the first electrode <NUM> and the second electrode <NUM>, or the first electrode <NUM> and the optical auxiliary layer <NUM>, may collectively define a microcavity structure, and a peak wavelength of an external quantum efficiency (EQE) spectrum in the second infrared wavelength region may be at least partially defined by a resonance wavelength of the microcavity structure. Details are the same as described above. As described herein, an element, property, or the like that is at least partially defined by another element, property, or the like may be understood to be associated with, or corresponding to, the other element, property, or the like.

The infrared sensor <NUM> may be applied to various fields for sensing light in the infrared wavelength region, for example, an image sensor for improving sensitivity in a low light environment, a sensor for increasing detection capability of 3D images by broadening the dynamic range for detailed black and white contrast, a security sensor, a vehicle sensor, a biometric sensor, or the like, and the biometric sensor may be, for example, an iris sensor, a depth sensor, a fingerprint sensor, a blood vessel distribution sensor, or the like, but is not limited thereto. The infrared sensor <NUM> may be for example applied to a CMOS infrared sensor or a CMOS image sensor.

<FIG> is a cross-sectional view showing an example of a sensor according to some example embodiments.

The sensor <NUM> according to some example embodiments includes a semiconductor substrate <NUM>, an insulation layer <NUM>, and an infrared sensor <NUM>. The semiconductor substrate <NUM> may correspond to substrate <NUM>.

The semiconductor substrate <NUM> may be a silicon substrate, and are integrated with a transfer transistor (not shown) and a charge storage <NUM>. The charge storage <NUM> may be integrated for each pixel. The charge storage <NUM> is electrically connected to the infrared sensor <NUM> and information of the charge storage <NUM> may be transferred by a transfer transistor.

A metal wire (not shown) and a pad (not shown) are formed on the semiconductor substrate <NUM>. The metal wire and pad may be made of a metal having low resistivity, for example, aluminum (Al), copper (Cu), silver (Ag), and alloys thereof to decrease signal delay, but are not limited thereto. Further, it is not limited to the structure, and the metal wire and pad may be disposed under the semiconductor substrate <NUM>.

The insulation layer <NUM> is formed on the metal wire and pad. The insulation layer <NUM> may be made of an inorganic insulating material such as a silicon oxide and/or a silicon nitride, or a low dielectric constant (low K) material such as SiC, SiCOH, SiCO, and SiOF. The insulation layer <NUM> has a trench <NUM> exposing the charge storage <NUM>. The trench <NUM> may be filled with fillers.

The aforementioned infrared sensor <NUM> is formed on the insulation layer <NUM>. The infrared sensor <NUM> includes the first electrode <NUM>, the second electrode <NUM>, the light absorbing layer <NUM> and the buffer layers <NUM> and <NUM>, as described above. The infrared sensor <NUM> may optionally further include the aforementioned optical auxiliary layer <NUM>, an anti-reflection layer, and/or an encapsulant. The infrared sensor <NUM> is as described above. The infrared sensors <NUM> may be arranged along rows and/or columns, for example, in a matrix arrangement.

Focusing lens (not shown) may be further formed on the infrared sensor <NUM>. The focusing lens may be configured to control a direction of incident light and gather the light in one region. The focusing lens may have a shape of, for example, a cylinder or a hemisphere, but is not limited thereto.

<FIG> is a cross-sectional view showing another example of a sensor according to some example embodiments.

The sensor according to some example embodiments may include a plurality of sensors having different functions, and the plurality of sensors having different functions may be stacked along a thickness direction of the semiconductor substrate <NUM>.

For example, the plurality of sensors having different functions may be an infrared sensor and/or an image sensor and, for example, independently selected and combined from a sensor for improving sensitivity in a low illumination environment, a sensor for increasing detection capability of 3D images by expanding the dynamic range for detailed division of black and white contrast, a security sensor, a vehicle sensor, a biometric sensor, and an image sensor. The image sensor may be configured to absorb and sense light in a red wavelength region, a green wavelength region, a blue wavelength region, or any combination thereof.

For example, the plurality of sensors may include two infrared sensors. For example, the plurality of sensors may include a first infrared light sensor configured to sense light having a first wavelength within the infrared wavelength region and a second infrared light sensor configured to sense light having a second wavelength within the infrared wavelength region.

The first wavelength and the second wavelength may be, for example, different each other within a wavelength region of greater than about <NUM> and less than or equal to <NUM>, and for example, the difference between the first wavelength and the second wavelength may be greater than or equal to about <NUM> and within the range, greater than or equal to about <NUM>, greater than or equal to about <NUM>, greater than or equal to about <NUM>, or greater than or equal to about <NUM>.

For example, either one of the first wavelength or the second wavelength may belong to a wavelength region of greater than or equal to about <NUM> and less than <NUM>, and the other one of the first wavelength or the second wavelength may belong to a wavelength region of about <NUM> to about <NUM>.

For example, the plurality of sensors may include one infrared sensor and one image sensor. For example, the plurality of sensors may have a stacked structure of the aforementioned infrared sensor and an image sensor configured to sense light in a red wavelength region, a green wavelength region, a blue wavelength region, or any combination thereof.

Referring to <FIG>, a sensor <NUM> according to some example embodiments includes an upper sensor <NUM>, the insulation layer <NUM>, the infrared sensor <NUM>, and the semiconductor substrate <NUM>. The upper sensor <NUM> and the infrared sensor <NUM> may be stacked.

The upper sensor <NUM> may be an infrared sensor or an image sensor.

The upper sensor <NUM> may be a photoelectric conversion device, and may include a lower electrode <NUM>, an upper electrode <NUM>, a light absorbing layer <NUM>, and buffer layers <NUM> and <NUM>. Either one of the lower electrode <NUM> or the upper electrode <NUM> may be an anode, and the other one may be a cathode. The light absorbing layer <NUM> may be configured to absorb light in the infrared wavelength region or the visible ray wavelength region. The light in the visible ray wavelength region may be light of the red wavelength region, the green wavelength region, the blue wavelength region, or the combination thereof. Light of the infrared wavelength region absorbed in the light absorbing layer <NUM> of the upper sensor <NUM> may not be overlapped with light in the infrared wavelength region sensed in the infrared sensor <NUM>. The buffer layers <NUM> and <NUM> may be a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an electron injection layer (EIL), an electron transport layer (ETL), a hole blocking layer (HBL), an optical auxiliary layer, or any combination thereof.

The infrared sensor <NUM> is as described above.

The insulation layer <NUM> is formed between the upper sensor <NUM> and the infrared sensor <NUM>. The insulation layer <NUM> has a trench <NUM> exposing the charge storage <NUM>, and the trench <NUM> may be filled with a filler.

The semiconductor substrate <NUM> is as described above, and the charge storage <NUM> is electrically connected to the first electrode <NUM> of the infrared sensor <NUM> or the lower electrode <NUM> of the upper sensor <NUM>.

The insulation layer <NUM> is formed between the infrared sensor <NUM> and the semiconductor substrate <NUM>. The insulation layer <NUM> has a trench <NUM> exposing the charge storage <NUM>, and the trench <NUM> may be filled with a filler.

<FIG> is a perspective view schematically showing another example of a sensor according to some example embodiments and <FIG> is a cross-sectional view schematically showing an example of the sensor of <FIG>.

Referring to <FIG> and <FIG>, the sensor <NUM> according to some example embodiments includes the semiconductor substrate <NUM>, the infrared sensor <NUM>, and the image sensor <NUM>. The image sensor <NUM> includes a red sensor 200a configured to sense light in the red wavelength region, a green sensor 200b configured to sense light in the green wavelength region, and a blue sensor 200c configured to sense light in the blue wavelength region.

The infrared sensor <NUM>, the red sensor 200a, the green sensor 200b, and the blue sensor 200c are arranged parallel to the surface of the semiconductor substrate <NUM> and respectively electrically connected to a charge storage <NUM> integrated in the semiconductor substrate <NUM>. The infrared sensor <NUM>, red sensor 200a, green sensor 200b and blue sensor 200c are individually photoelectric conversion devices.

The red sensor 200a includes a lower electrode 210a, a red light absorbing layer 230a, an upper electrode 220a, and buffer layers 240a and 250a. The green sensor 200b includes a lower electrode 210b, a green light absorbing layer 230b, an upper electrode 220b, and buffer layers 240b and 250b. The blue sensor 200c includes a lower electrode 210c, a blue light absorbing layer 230c, an upper electrode 220c and buffer layers 240c and 250c. The red light absorbing layer 230a may be configured to selectively absorb light in the red wavelength region and photoelectrically convert it, the green light absorbing layer 230b may be configured to selectively absorb light in the green wavelength region and photoelectrically convert it, and the blue light absorbing layer 230c may be configured to selectively absorb light in the blue wavelength region and photoelectrically convert it. The lower electrodes 210a, 210b, and 210c and the upper electrodes 220a, 220b, and 220c may be individually light-transmitting electrodes. The red light absorbing layer 230a, the green light absorbing layer 230b, and the blue light absorbing layer 230c may independently include an inorganic light absorbing material, an organic light absorbing material, an organic-inorganic light absorbing material, or any combination thereof, and for example, at least one of the red light absorbing layer 230a, the green light absorbing layer 230b, or the blue light absorbing layer 230c may include the organic light absorbing material. At least one of buffer layers 240a, 240b, 240c, 250a, 250b, or 250c may be omitted.

Referring to <FIG> and <FIG>, the sensor <NUM> according to some example embodiments includes a semiconductor substrate <NUM>, an infrared sensor <NUM>, an image sensor <NUM>, and an insulation layer <NUM>.

The image sensor <NUM> includes the red sensor 200a configured to sense light in the red wavelength region, the green sensor 200b configured to sense light in the green wavelength region, and the blue sensor 200c configured to sense light in the blue wavelength region.

The infrared sensor <NUM> and the image sensor <NUM> are stacked along the thickness direction of the semiconductor substrate <NUM>. For example, the infrared sensor <NUM> is disposed below, and the image sensor <NUM> is disposed on the upper portion thereof. In the drawing, the structure of sequentially staking the red sensor 200a, the green sensor 200b, and the blue sensor 200c are shown as an example according to some example embodiments, but the red sensor 200a, the green sensor 200b, and the blue sensor 200c may be variously stacked.

The infrared sensor <NUM>, the red sensor 200a, the green sensor 200b, and the blue sensor 200c are as described above.

The infrared sensor <NUM>, the red sensor 200a, the green sensor 200b, and the blue sensor 200c are each electrically connected to the charge storages <NUM> integrated in the semiconductor substrate <NUM>. Between the semiconductor substrate <NUM> and the infrared sensor <NUM> and between the infrared sensor <NUM> and the image sensor <NUM>, each insulation layer 80a, 80b, 80c, and 80d is disposed.

The aforementioned sensors may be applied to various electronic devices, for example, mobile phones, digital cameras, biometric devices, security devices, and/or automobile electronic components, but is not limited thereto.

<FIG> is a schematic diagram of an electronic device according to an example.

Referring to <FIG>, an electronic device <NUM> includes a processor <NUM>, a memory <NUM>, a sensor <NUM>, and a display device <NUM> (e.g., a light emitting diode (LED) display panel device, an organic LED (OLED) display panel device, or the like) electrically connected through a bus <NUM>. The sensor <NUM> may be the aforementioned sensor <NUM>. The sensor <NUM> may be any sensor, infrared sensor, or the like according to any of the example embodiments (e.g., infrared sensor <NUM>, image sensor <NUM>, and/or sensor <NUM>). The processor <NUM> may perform a memory program and thus at least one function. The processor <NUM> may additionally perform a memory program and thus display an image on the display device <NUM>. The processor <NUM> may generate an output.

The memory <NUM> may be a non-transitory computer readable medium and may store a program of instructions. The memory <NUM> may be a nonvolatile memory, such as a flash memory, a phase-change random access memory (PRAM), a magneto-resistive RAM (MRAM), a resistive RAM (ReRAM), or a ferro-electric RAM (FRAM), or a volatile memory, such as a static RAM (SRAM), a dynamic RAM (DRAM), or a synchronous DRAM (SDRAM). The processor <NUM> may execute the stored program of instructions to perform one or more functions. For example, the processor <NUM> may be configured to process electrical signals generated by the sensor <NUM>. The processor <NUM> may include processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitry more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. The processor <NUM> may be configured to generate an output (e.g., an image to be displayed on the display device <NUM>) based on such processing.

Hereinafter, some example embodiments are illustrated in more detail with reference to examples. However, the present scope of the inventive concepts is not limited to the examples.

A triphenylamine derivative is deposited on an Ag reflective plate to form a lower buffer layer. Subsequently, on the lower buffer layer, Sn naphthaloxyanine (a near-infrared absorbing material (A), a p-type semiconductor) and C60 (a counter material (B), an n-type semiconductor) are co-deposited in a thickness ratio (a volume ratio) shown in Table <NUM> to form a light absorbing layer. Then, on the light absorbing layer, C60 is deposited to form an upper buffer layer, and silver (Ag) is deposited to be <NUM> thick on the upper buffer layer to form a <NUM>-thick upper electrode. Subsequently, on the upper electrode, aluminum oxide (Al<NUM>O<NUM>) is deposited to be <NUM>, and sequentially, silicon oxynitride (SiON) is deposited to be <NUM> thick to manufacture an infrared sensor.

Thicknesses of the lower buffer layer, the light absorbing layer, and the upper buffer layer and a composition ratio (a thickness ratio or a volume ratio) in the light absorbing layer are shown in Table <NUM>.

Infrared sensors are manufactured according to the same method as Example <NUM> except that ITO is sputtered to form a <NUM>-thick upper electrode instead of depositing silver (Ag), and then, aluminum oxide (Al<NUM>O<NUM>) and silicon oxynitride (SiON) are sequentially deposited thereon to have thicknesses shown in Table <NUM>.

On a glass substrate, ITO is sputtered to form a <NUM>-thick lower electrode. Subsequently, on the ITO electrode, a triphenylamine derivative is deposited to form a <NUM>-thick lower buffer layer. On the lower buffer layer, Sn-naphthaloxyanine (a near-infrared absorbing material (A), a p-type semiconductor) and C60 (a counter material (B), an n-type semiconductor) are co-deposited in a thickness ratio (or a volume ratio) of <NUM>:<NUM> to form a <NUM>-thick light absorbing layer. On the light absorbing layer, C60 is deposited to form a <NUM>-thick upper buffer layer, and ITO is sputtered thereon to form a <NUM>-thick upper electrode. On the upper electrode, aluminum oxide (Al<NUM>O<NUM>) is deposited to be <NUM> thick, and sequentially, silicon oxynitride (SiON) is deposited to be <NUM> thick to produce an infrared sensor.

An infrared sensor is manufactured according to the same method as Example <NUM> except that silicon naphthalocyanine (Si-naphthalocyanine) is used instead of the Sn naphthaloxyanine.

Optical spectra in an infrared wavelength region of the infrared sensors according to Examples and Comparative Examples are evaluated.

<FIG> is an optical spectrum of the infrared sensor according to Example <NUM> and <FIG> is an optical spectrum of the infrared sensor according to Comparative Example <NUM>.

Referring to <FIG>, the absorption spectrum of the infrared sensor according to Example <NUM> includes a main absorption spectrum having a maximum absorption wavelength (λmax) in a wavelength region of greater than about <NUM> and less than about <NUM> and a sub-absorption spectrum having particular (or, alternatively, predetermined) absorption intensity (Abs<NUM>/Abs<NUM>≥ <NUM>) in a wavelength region of greater than or equal to about <NUM> (e.g., about <NUM> to about <NUM>).

On the contrary, referring to <FIG>, the absorption spectrum of the infrared sensor according to Comparative Example <NUM> includes a main absorption spectrum having a maximum absorption wavelength (λmax) in a wavelength region of greater than about <NUM> and less than about <NUM> but no sub-absorption spectrum having particular (or, alternatively, predetermined) absorption intensity (Abs<NUM>/Abs<NUM> ≥ <NUM>) in a wavelength region of greater than or equal to about <NUM>.

Photoelectric conversion efficiency and detection selectivity of the infrared sensors according to Examples and Comparative Examples are evaluated.

The photoelectric conversion efficiency is evaluated from an EQE maximum value (EQEmax) (also referred to herein interchangeably as a maximum EQE value) in an EQE spectrum and in detail, is evaluated by an IPCE (Incident Photon to Current Efficiency) method in a wavelength region of <NUM> to <NUM> at <NUM> V.

Detection selectivity of the sensors is evaluated from a full width at half maximum (FWHM) in the EQE spectrum shown in a wavelength region of greater than or equal to <NUM>.

The results are shown in Table <NUM> and <FIG>.

<FIG> are EQE spectra in the infrared wavelength region of the infrared sensors according to Examples <NUM> to <NUM>, respectively, <FIG> is an EQE spectrum in the infrared wavelength region of the infrared sensor according to Comparative Example <NUM>, and <FIG> is an EQE spectrum of the infrared wavelength region of the infrared sensor according to Comparative Example <NUM>.

Referring to Table <NUM> and <FIG>, the infrared sensors according to Examples, unlike the infrared sensors according to Comparative Examples, exhibit amplified EQE spectra in a wavelength region of greater than about <NUM> (e.g., about <NUM> to about <NUM>, about <NUM> to about <NUM>, etc.).

In addition, when the EQE spectra of the infrared sensors according to Examples <NUM>, <NUM>, and <NUM> to <NUM> are compared, peak wavelengths of the EQE spectra are shifted depending on the thicknesses of the lower buffer layers, and specifically, as the thicknesses of the lower buffer layers are greater, the peak wavelengths of the EQE spectra are shifted toward a longer wavelength region.

In addition, comparing the EQE spectra of the infrared sensors according to Examples <NUM> to <NUM>, <NUM>, and <NUM>, peak wavelengths of the EQE spectra are shifted depending on thicknesses of the upper buffer layers, and specifically, as the thicknesses of the upper buffer layers are greater, the peak wavelengths of the EQE spectra are shifted toward the longer wavelength region.

In addition, comparing the EQE spectra of the infrared sensors according to Examples <NUM> to <NUM>, the peak wavelengths of the EQE spectra are shifted depending on the thicknesses of the light absorbing layers, and specifically, as the thicknesses of the light absorbing layer are greater, the peak wavelengths of the EQE spectra are shifted toward the longer wavelength region.

In addition, comparing the EQE spectra of the infrared sensors according to Examples <NUM> and <NUM>, peak wavelengths of the EQE spectra are shifted according to composition ratios of the light absorbing layers, and specifically, as the composition ratio of the near-infrared absorbing material of the light absorbing layers is higher, the peak wavelengths of the EQE spectra are shifted toward the longer wavelength region.

In addition, comparing the EQE spectra of the infrared sensors according to Examples <NUM> to <NUM>, peak wavelengths of the EQE spectra are shifted according to thickness ratios of the optical auxiliary layers, and specifically, as thickness ratios of the high refractive index layers and the low refractive index layers are larger, the peak wavelengths of the EQE spectra are shifted toward the longer wavelength region.

Claim 1:
A sensor (<NUM>; <NUM>; <NUM>), comprising:
a first electrode (<NUM>; <NUM>), the first electrode (<NUM>; <NUM>) including a reflective layer;
a second electrode (<NUM>; <NUM>), the second electrode (<NUM>; <NUM>) facing the first electrode (<NUM>; <NUM>); and
a light absorbing layer (<NUM>; <NUM>) between the first electrode (<NUM>; <NUM>) and the second electrode (<NUM>; <NUM>),
wherein the light absorbing layer (<NUM>; <NUM>) has a first absorption spectrum having a first absorption peak in a first infrared wavelength region and a second absorption spectrum having a second absorption peak in a second infrared wavelength region, wherein the second absorption spectrum does not at least partially overlap with the first absorption spectrum, wherein the second infrared wavelength region is a region having a longer wavelength than that of the first infrared wavelength region,
wherein the second absorption spectrum has a lower absorption intensity than the first absorption spectrum, and
wherein an external quantum efficiency, EQE, spectrum in the second infrared wavelength region is amplified such that: a variance of a local maximum EQE value, EQEmax, of the EQE spectrum from a remainder of EQE values of the EQE spectrum in the second infrared wavelength region is greater than a variance of the second absorption peak from a remainder of absorption intensities of the second absorption spectrum in the second infrared wavelength region, and/or
a full width at half maximum, FWHM, of the EQE spectrum in the second infrared wavelength region is narrower than a full width at half maximum, FWHM, of the second absorption spectrum in the second infrared wavelength region.