Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7929318 | Optics Communications | 2015 | 4 Pages |
Abstract
The modulation transfer function (MTF) of graded band-gap AlGaAs/GaAs reflection-mode photocathodes was determined using two-dimensional Poisson and continuity equations through numerical method. Based on the MTF model, we calculated the theoretical MTF of graded and uniform band-gap reflection-mode photocathodes. We then analyzed the effects of Al composition, wavelength of incident photon, and thicknesses of AlGaAs and GaAs layer on the resolution. Calculation results show that graded band-gap structures can increase the resolution of reflection-mode photocathodes. When the spatial frequency is 800Â lp/mm and wavelength is 600 nm, the resolution of graded band-gap photocathodes generally increases by 15.4-29.6%. The resolution improvement of graded band-gap photocathodes is attributed to the fact that the built-in electric field in graded band-gap photocathodes reduces the lateral diffusion distance of photoelectrons.
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
Wenjuan Deng, Daoli Zhang, Jijun Zou, Xincun Peng, Weilu Wang, Yijun Zhang, Benkang Chang,