Open AccessNegative electron affinity GaAs wire-array photocathodes
Author(s) -
JiJun Zou,
Xiaowan Ge,
Yijun Zhang,
Wei Deng,
Zong-Hong Zhu,
Weilu Wang,
Xincun Peng,
Zhaoping Chen,
Benkang Chang
Publication year - 2016
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.004632
Subject(s) - photocathode , materials science , wafer , photoluminescence , optoelectronics , scanning electron microscope , quantum efficiency , inductively coupled plasma , optics , etching (microfabrication) , etch pit density , reactive ion etching , electron , plasma , nanotechnology , physics , layer (electronics) , quantum mechanics , composite material
Negative electron affinity GaAs wire-array photocathodes have been fabricated by reactive ion etching and inductively coupled plasma etching of bulk GaAs material followed by Cs-O activation. Scanning electron microscope has revealed that the thus obtained high-density GaAs wire arrays had high periodicity, large height, and good morphology. Photoluminescence spectra indicated the wire arrays were of good crystalline quality and free from any obvious damage. Compared to the original GaAs wafer, the photoluminescence peak positions of the wire arrays were somewhat red-shifted, which may be attributed to the temperature effect and strain relaxation. The wire-array structures showed significantly reduced light reflection compared with the original wafer due to the excellent light-trapping effect. Cs-O activation experiments of the GaAs wire arrays have been performed to reveal the effect of incident angle on quantum efficiency. The results show that maximum quantum efficiency was obtained at about 30°. Given these unique electrical and optical properties, a GaAs wire-array photocathode is an attractive alternative to its planar-structured counterpart.