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Proceedings Paper

Effect of different buffer-layers on near-infrared response of GaAs photocathodes
Author(s): Yijun Zhang; Cheng Feng; Feng Shi; Xiaohui Wang; Xinxin Liu; Xiang Zhang; Yunsheng Qian
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Paper Abstract

In view that enhancing near-infrared response of photocathodes is critical to the detection performance, we propose two technical approaches by changing the structure of buffer-layer underneath the active-layer, wherein one is to produce a graded band gap using the graded-composition structure, and the other is to produce a distributed Bragg reflector using the AlAs/GaAs supperlattice structure. Three types of reflection-mode GaAs photocathode samples grown by molecular beam epitaxy were prepared under the same condition. By comparison of activation photocurrent and spectral response among the three different samples, it is found that compared with the conventional sample, the samples with graded-composition and distributed Bragg reflector can obtain higher photocurrent and better response. The measured results of spectral response indicate that the samples without a distributed Bragg reflector exhibit a typical smooth spectral behavior, while the spectral response of the sample with a distributed Bragg reflector structure has a different resonance feature. The sample with the distributed Bragg reflector structure can obtain higher response than those without distributed Bragg reflector at some near-infrared wavelength positions. The peak positions of spectral response curve agree quite well with the dip positions in the reflectivity spectrum. This agreement demonstrates that the response enhancements are ascribed to the resonant absorption effect.

Paper Details

Date Published: 28 April 2017
PDF: 6 pages
Proc. SPIE 10209, Image Sensing Technologies: Materials, Devices, Systems, and Applications IV, 1020918 (28 April 2017); doi: 10.1117/12.2261658
Show Author Affiliations
Yijun Zhang, Nanjing Univ. of Science and Technology (China)
Cheng Feng, Nanjing Univ. of Science and Technology (China)
Feng Shi, Science and Technology on Low-Light-Level Night Vision Lab. (China)
Xiaohui Wang, Univ. of Science and Technology of China (China)
Xinxin Liu, Nanjing Univ. of Science and Technology (China)
Xiang Zhang, Nanjing Univ. of Science and Technology (China)
Yunsheng Qian, Nanjing Univ. of Science and Technology (China)

Published in SPIE Proceedings Vol. 10209:
Image Sensing Technologies: Materials, Devices, Systems, and Applications IV
Nibir K. Dhar; Achyut K. Dutta, Editor(s)

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