Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al conce...

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Bibliographic Details
Published in:Journal of applied physics 2015-01, Vol.117 (2)
Main Authors: Shasti, M., Mortezaali, A., Dariani, R. S.
Format: Article
Language:English
Subjects:
ALUMINIUM
ALUMINIUM COMPOUNDS
Aluminum
Carrier transport
COMPARATIVE EVALUATIONS
CONCENTRATION RATIO
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Current voltage characteristics
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
Electrodes
HETEROJUNCTIONS
ILLUMINANCE
Illumination
LAYERS
Morphology
P-TYPE CONDUCTORS
PHOTODETECTORS
Photodiodes
Photoelectric effect
Photoelectric emission
Photometers
PYROLYSIS
SCANNING ELECTRON MICROSCOPY
SILICON
Spray pyrolysis
SURFACES
Ultraviolet detectors
ULTRAVIOLET RADIATION
X-RAY DIFFRACTION
Zinc oxide
ZINC OXIDES
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Summary:In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4905416