title: Resolution characteristics of graded doping and graded composition transmission-mode AlGaAs/GaAs photocathodes.
abstract: The resolution model of a graded doping and graded composition transmission-mode AlGaAs/GaAs photocathode is solved numerically from the two-dimensional continuity equations. According to the model, we calculate the theoretical modulation transfer function (MTF) of different graded doping and graded composition structures. The simulation results show that both graded composition and graded doping structures can increase the resolution of the photocathode. The exponentially doping and linear composition photocathode has the maximum resolution among the possible graded doping and graded composition photocathodes. The resolution improvement is attributed to the built-in electric field induced by a graded composition or graded doping structure. The simulation results also show that the MTFs of AlGaAs/GaAs cathodes increase as the AlGaAs layer thickness decreases, or the incident light wavelength increases.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Deng
authors.forename: Jijun
authors.initials: J
authors.lastname: Zou
authors.forename: Xincun
authors.initials: X
authors.lastname: Peng
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
authors.forename: Zhifu
authors.initials: Z
authors.lastname: Zhu
authors.forename: Weilu
authors.initials: W
authors.lastname: Wang
authors.forename: Yijun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Benkang
authors.initials: B
authors.lastname: Chang