Search query: Al doped  film photodetector

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abstract: Ultraviolet (UV) detection properties of undoped ZnO and Al doped ZnO (AZO) based interdigitated metal semiconductor metal (MSM) structure are investigated in this paper. High quality of fibrous Al doped ZnO thin films with enhanced conductivity and optical response with controlled doping of Al are synthesized using low cost sol gel method. The surface morphology and absorption properties of the films have been investigated. The responsivity and detectivity characteristics of both the devices are compared over 300 700 nm wavelengths. The Al doped ZnO based Ag/AZO/Ag MSM structure show the maximum responsivity and detectivity of ~5.63 A/W and <inline formula> <tex math notation="LaTeX"\sim 1.8\times 10 {12} /tex math>/inline formula> cmHz<sup>1/2</sup>W<sup> 1</sup> while the respective values for the Ag/undoped ZnO/Ag photodetector are ~3.65 A/W and <inline formula> <tex math notation="LaTeX"\sim 1.3\times 10 {12} /tex math>/inline formula> cmHz<sup>1/2</sup>W<sup> 1</sup> at 365 nm and <inline formula> <tex math notation="LaTeX"$34~\mu \text{W} /tex math>/inline formula>/cm<sup>2</sup> incident UV intensity. The proposed AZO based MSM photodetector has smaller rise time ~30 s) than that ~35 s) of the undoped ZnO based MSM photodetector. However, the AZO based device shows slightly poor spectrum selectivity over the undoped ZnO based device.
author_names: Chandan Kumar

Bhoopendra Kumar Kushwaha

Amit Kumar

Deepak Kumar Jarwal

Rishibrind Kumar Upadhyay

Abhinav Pratap Singh

Satyabrata Jit
title: Fibrous Al Doped ZnO Thin Film Ultraviolet Photodetectors With Improved Responsivity and Speed
venue: IEEE Photonics Technology Letters
year: 2020

abstract: Abstract This paper presents the synthesis of undoped and 2 wt. titanium (Ti) doped zinc oxide (ZnO) thin films onto glass substrates by chemical spray pyrolysis technique. Both films are deposited at 375 degC substrate temperature. The influence of Ti doping on structural, morphological, optical and UV detection properties of ZnO film was studied. Both films revealed to be of polycrystalline nature with a hexagonal wurtzite structure; and the ZnO film crystallinity improved on Ti doping. Surface morphological observations agreed well with structural results. The Ti incorporation in ZnO thin films were confirmed by an energy dispersive X ray spectroscopic analysis (EDX) The Ti doping increased the optical transmittance ~96% at 550) and band gap ~3.2927 eV) of ZnO thin film. Further, the metal semiconductor metal (MSM) planar ultraviolet photodetectors (UV PDs) were fabricated from deposition of tin (Sn) contacts onto undoped and Ti doped ZnO films using e beam evaporation technique. To investigate UV photodetection properties, the MSM devices were subjected to current voltage (I V) characteristics measurements of forward and reverse bias in dark and UV light conditions. The photocurrent and responsivity were measured as a function of optical power density and applied voltage, respectively. The reproducibility of the UV detection performance of MSM devices was ensured by constantly switching UV light on and off at regular time intervals. The Ti doped ZnO film based UV PD demonstrates highest responsivity of about 0.051 A/W upon 2 mW/cm2 illumination at 365 nm peak wavelengths and 5 V applied bias.
author_names: Prashant Shivaji Shewale

N K Lee

Seung Hee Lee

Kwang-yong Kang

Y Shane Yu
title: Ti doped ZnO thin film based UV photodetector: Fabrication and characterization
year: 2015

abstract: Abstract An n ZnO nanorods/ p Si heterojunction photodetector with Al doped ZnO (AZO) as an electron transporting layer was fabricated. The heterojunction with 20 nm AZO film showed a better characteristic than that of the device without AZO, and it displays a rectification ratio of 8470 at 3 V and a turn on voltage of 1.8 V. Also, based on spectral responsivity measurement, the device with AZO coating showed higher responsivity and better visible blind detectivity than those without AZO, and the peak responsivity of the photodetector with AZO was as high as ~0.49 A/W at 354 nm. Furthermore, the photodetector with AZO layer showed a bigger UV visible responsivity ratio R 354 nm R 546 nm than that of the photodetector without AZO coating at 2 V. The role of AZO layer was illustrated through energy band theory and the electron transport mechanism.
author_names: Hai Zhou

Jun Mei

Pengbin Gui

Pan Tao

Zehao Song

Hao Wang

Guojia Fang
title: The investigation of Al doped ZnO as an electron transporting layer for visible blind ultraviolet photodetector based on n ZnO nanorods/p Si heterojunction
year: 2015

abstract: A Sb doped ZnO microrod array was fabricated on an Al doped ZnO thin film by electrodeposition. Strong violet luminescence, originated from free electron to acceptor level transitions, was identified by temperature dependent photoluminescence measurements. This acceptor related transition was attributed to substitution of Sb dopants for Zn sites, instead of O sites, to form a complex with two Zn vacancies (VZn) the SbZn 2VZn complex. This SbZn 2VZn complex has a lower formation energy and acts as a shallow acceptor which can induce the observed strong violet luminescence. The photoresponsivity of our ZnO p n homojunction device under a negative bias demonstrated a nearly 40 fold current gain, illustrating that our device is potentially an excellent candidate for photodetector applications in the ultraviolet wavelength region.
author_names: Wei-Jen Chen

Jen-Kai Wu

Jheng-Cyuan Lin

Shun-Tsung Lo

Huang De Lin

D R Hang

Ming-feng Shih

Chi-Te Liang

Yuan Huei Chang
title: Room temperature violet luminescence and ultraviolet photodetection of Sb doped ZnO/Al doped ZnO homojunction array
venue: Nanoscale Research Letters
year: 2013

abstract: ZnO and Al doped ZnO (AZO) thin films were grown on the ZnO buffer layer by a chemical spray pyrolysis method. The metal semiconductor metal (MSM) UV photodetector based on ZnO thin films with two device configuration Ag/AZO/ZnO/Ag and Ag/ZnO/ZnO/Ag have been studied. AZO and ZnO thin films were grown on the ZnO buffer layer by a chemical spray pyrolysis technique. The effect of the buffer layer on the physicochemical and UV sensing properties of the AZO and ZnO thin film based UV photodetectors were analyzed. The XRD results suggested that the buffer layer improves the crystalline quality of the ZnO thin films. The device with configuration Ag/AZO/ZnO/Ag exhibits a maximum photocurrent of about 876 uA at 5 V bias at 365 nm peak wavelength. The linear I V characteristic of the photodetector reveals the good ohmic contacts between metal semiconductor junctions. The AZO based UV photodetector with ZnO buffer layer shows a maximum photoresponsivity of about 340 A/W, which is much higher than that of the ZnO based UV photodetector with ZnO buffer layer. The photoresponse and photoswitching characteristics of the device demonstrate that a ZnO UV photodetector with a buffer layer offers a new way to fabricate devices on a buffer layer coated substrate.
author_names: S I Inamdar

V V Ganbavle

Sohel Khalil Shaikh

K Y Rajpure
title: Effect of the buffer layer on the metal semiconductor metal UV photodetector based on Al doped and undoped ZnO thin films with different device structures
year: 2015

abstract: Abstract The structural, optical, and electrical properties of undoped and Al doped ZnO films deposited on p Si (001) substrate were studied using DC unbalanced magnetron sputtering. This study is motivated by the absence of detail reports concerning the orbital states inducing the optical bandgap (Eg) blueshift. Besides, the influences of Al on the possible modification of point defect and the photodetecting performance are highlighted to offer guidelines for better development in ZnO based photodetector. It was found that the Al doping reduced the grain size. The doping increased the lattice parameters and slightly decreased the local symmetry distortion at ZnO4. From the absorbance spectra, the doping increased Eg of ZnO film (3.28 3.36 eV) induced by the Burstein Moss effect. From the density functional calculation, the Burstein Moss effect induced Eg from the valence band maximum (VBM) to Fermi level located above the lowest Zn 4s conduction state. From the photoluminescence spectra, the undoped film showed the transitions from O vacancy, Zn interstitial, and free exciton states to the VBM. The doped film showed the transitions from Zn interstitial to O interstitial and few Zn vacancy states at the cost of O vacancies. Moreover, the energy level of free exciton states slightly decreased. Notably, O interstitials increased the lattice parameters. From the electrical properties, the doping enhanced the ultraviolet region photo to dark current ratio up to 3.044 V, leading to the photodetecting sensitivity enhancement. This study emphasizes the significant effect of Al doping on the optical absorbance, point defect evolution, and photodetecting performance of ZnO film for low voltage ultraviolet photodetector applications.
author_names: Ni'matul Azizah

Shibghatullah Muhammady

Muhammad Abiyyu Kenichi Purbayanto

Eka Nurfani

Toto Winata

Euis Sustini

Rena Widita

Yudi Darma
title: Influence of Al doping on the crystal structure, optical properties, and photodetecting performance of ZnO film
year: 2020

abstract: The maximum of spectral sensitivity of ZnO based photodetectors can be shifted to deep UV photon range of ~250 to 300 nm by Mg dosing [1, 2] However heavily Mg doped ZnO shows very poor conductance and optical properties, which limits its use as a sensitive element of deep UV SAW photodetector. The simultaneously doped ZnO by Mg and Al atoms may assist in tuning electrical, optical and structural properties of ZnO in wide range and opens the possibility to use Zn1 x yMgxAlyO films for deep UV detector integrated to SAW device. Apart from dopant related aspects the structural and optical quality of a film prepared by PLD method is heavily influenced by the film/nanostructure growth temperature and oxygen pressure. We study optical, structural, lattice vibration modes and photoelectric properties of Zn1 x yMgxAlyO films on LiNbO3 substrates designed by PLD method at different oxygen pressure and growth temperatures to optimize their properties for using as a deep UV sensitive element of surface acoustic wave (SAW) photodetector. The optical absorption band edge for optimized Zn0.52Mg0.19Al0.007O/LiNbO3 film was shifted to 320 nm and the corresponding photodetector demonstrates high sensitivity and fast photoelectric response towards 248 nm laser light.
author_names: M E Kutepov

Vladimir E Kaydashev

G Ya Karapetyan

D A Zhilin

Tatevik Minasyan

A S Anokhin

Anatoly Chernyshev

Kamaludin Abdulvakhidov

Ekaterina Glazunova

Vladimir Irkha

E M Kaidashev
title: Optimization of Zn 1 x y Mg x Al y O Film Properties to Use in Deep UV SAW Photodetector
year: 2019

abstract: Abstract The Cu 2 O films were electrodeposited on ZnO nanorod arrays (NRs) and the Cu 2 O/ZnO NRs heterojunctions were formed. The optical electronic response of the heterojunctions was investigated. The diameter size and crystal quality of ZnO NRs were modified by the seed layer. ZnO NRs with good crystal quality were obtained on the 0.5% Al doped ZnO seed layer film (named as AZO (0.5% The devices based on the Cu 2 O/ZnO NRs heterojunction exhibit excellent stability and reproducibility of the self powered photoresponse properties. The device with AZO (0.5% seed layer demonstrates the high photoresponsivity of 60 70 mA/W in the violet and blue light with a fast response speed at zero applied bias.
author_names: Chang Wang

Jianping Xu

Shaobo Shi

Yuzhu Zhang

Yanyan Gao

Zeming Liu

Xuguang Zhang

Lan Li
title: Optimizing performance of Cu2O/ZnO nanorods heterojunction based self powered photodetector with ZnO seed layer
year: 2017

abstract: Organic position sensitive detector (OPSD) based on copper phthalocyanine CuPc:fullerene C60 bulk heterojunction with an inverted structure have been fabricated using aluminum doped ZnO (ZnO:Al) as a resistive layer, which is prepared by sol gel method. The resistance length of the one dimensional PSD is fixed at 5 mm, and the Ag common electrode is fabricated by vacuum evaporation within the 100 um width. The current density voltage characteristics with different structures of photodetector, the influence of ZnO:Al resistivity on the thickness and the position characteristics of PSDs are investigated. The experimental results indicate that the architecture, which uses an inverted structure, increases sensitivity under red light illumination compared to the conventional structure. In addition, the thickness of the ZnO:Al has influence on the position characteristics. The resistivity of ZnO:A film with Al doping concentration of 2 mol% prepared in this study is around 150 Ocm and it increases from less than approximately 400 nm thickness. These characteristics seem to be correlated with the properties of ZnO:AI resistive layer. For a device with a 620 nm thick ZnO:Al layer, the measured position values obtained from the output photocurrent agree with the actual position values under red laser light illumination. CuPc:C60 OPSD with an inverted structure exhibits red light sensitivity, high incident photon to current conversion efficiency of above 80% at 3 V and linearity error of 5.9% at 2 V.
author_names: Taichiro Morimune

Hirotake Kajii

Hiroki Nishimaru

Shinji Ono
title: Organic Position Sensitive Detectors Based on ZnO:Al and CuPc:C60.
venue: Journal of nanoscience and nanotechnology
year: 2016

abstract: Thin film heterojuction of the type p ZnO/n GaN was prepared by spray pyrolysis and electron beam evaporation technique, respectively. Hall measurements demonstrate the firm p type conductivity of the p doped ZnO film. The structural and electrical properties of the p ZnO/n GaN heterojunction are investigated by X ray diffraction (XRD) and current voltage (I V) measurements. The XRD shows that the p ZnO/n GaN heterojunction is highly crystalline in nature with preferred orientation along the [0001] direction. The current voltage curve of the heterojunction demonstrates obvious rectifying diode behavior in the dark and under illumination conditions. The ideality factor of the detector was determined in case of forward bias at low voltages and it was found to be 13.35. The turn on voltage appears at about 1V under forward biased voltage, and the reverse breakdown voltage is about 4V. It was found that the current of the illumination increases with the increase of bias voltages.
author_names: Abla Al-Zouhbi

Nasser Saad Al-Din

M O Manasreh
title: Characteristics of p ZnO/n GaN heterojunction photodetector
year: 2012