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Proceedings Paper

The response time of GaN photoconductive detector under various ultraviolet-radiation intensities
Author(s): Jintong Xu; Yinwen Tang; Xiangyang Li; Haimei Gong; Degang Zhao
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Paper Abstract

The persistent photoconductivity (PPC) effect was generally observed in many III-V compound semiconductors and it was always related to yellow luminescence. In this paper, the PPC effect in unintentionally doped GaN was investigated. The GaN photoconductive detector response time measured by changing the chopper frequency of modulator was studied under various ultraviolet-radiation intensities. The maximum value of UV intensities used in test was approximately 0.2W/m2. Experimental results show that the response time of unintentionally doped GaN PC detector is independent of the wavelength of the ultraviolet radiation in the range of 300~365nm and it decreases with the increasing of UV radiation intensity. The longest response time getting in experiments was 7.64ms and the shortest 2.89ms. Fourier transformation and lock-in amplifier was used to reduce the noise at AC frequency of 50Hz and the results show that Fourier transformation was more effective to eliminate the low frequency noise. The experimental data fit the theoretical curve very well, better than the results reported previously. Finally, these phenomena were tried to be explained using a mechanism that minor carriers were captured by deep acceptors. The deep acceptors were deduced to be VGa related complexes. In strong UV radiation, the photo-generated holes (minor carriers) were no longer captured by deep acceptors and the recombination opportunities with majority carriers were increased. Consequently the response time was reduced. The other possible reason was that there were metastable states which were related to Ga vacancy.

Paper Details

Date Published: 17 October 2005
PDF: 7 pages
Proc. SPIE 5964, Detectors and Associated Signal Processing II, 59640Z (17 October 2005); doi: 10.1117/12.625061
Show Author Affiliations
Jintong Xu, Shanghai Institute of Technical Physics, CAS (China)
Yinwen Tang, Shanghai Institute of Technical Physics, CAS (China)
Xiangyang Li, Shanghai Institute of Technical Physics, CAS (China)
Haimei Gong, Shanghai Institute of Technical Physics, CAS (China)
Degang Zhao, Institute of Semiconductor, CAS (China)

Published in SPIE Proceedings Vol. 5964:
Detectors and Associated Signal Processing II
Jean-Pierre Chatard; Peter N. J. Dennis, Editor(s)

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