Low dark current and high speed ZnO metal–semiconductor–metal photodetector on SiO2/Si substrate

Date
2014
Advisor
Instructor
Source Title
Applied Physics Letters
Print ISSN
0003-6951
Electronic ISSN
Publisher
AIP Publishing
Volume
105
Issue
16
Pages
161108-1 - 161108-3
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

ZnO thin films are deposited by radio-frequency magnetron sputtering on thermally grown SiO2 on Si substrates. Pt/Au contacts are fabricated by standard photolithography and lift-off in order to form a metal-semiconductor-metal (MSM) photodetector. The dark current of the photodetector is measured as 1 pA at 100V bias, corresponding to 100 pA/cm(2) current density. Spectral photoresponse measurement showed the usual spectral behavior and 0.35 A/W responsivity at a 100V bias. The rise and fall times for the photocurrent are measured as 22 ps and 8 ns, respectively, which are the lowest values to date. Scanning electron microscope image shows high aspect ratio and dense grains indicating high surface area. Low dark current density and high speed response are attributed to high number of recombination centers due to film morphology, deducing from photoluminescence measurements. These results show that as deposited ZnO thin film MSM photodetectors can be used for the applications needed for low light level detection and fast operation. (C) 2014 AIP Publishing LLC.

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Other identifiers
Book Title
Keywords
Thin-film, Ultraviolet Detectors, Fast Photoresponse
Citation
Published Version (Please cite this version)