The optimal thickness of a transmission-mode GaN photocathode

• 作 者: 王晓晖 石峰 郭晖 胡仓陆 程宏昌 常本康 任玲 杜玉杰 张俊举
• 机 构: Science and Technology on Low-Light-Level Night Vision Laboratory,Institute of Electronic Engineerin
• 出 处: Chinese Physics B
• 发表日期: 2012年08期
• 关键词: fitting fitted affinity recombination doping chamber thick reaches ultrahigh len

A 150-nm-thick GaN photocathode with a Mg doping concentration of 1.6×1017cm-3 is activated by Cs/O in an ultrahigh vacuum chamber,and a quantum efficiency(QE) curve of the negative electron affinity transmission-mode(t-mode) of the GaN photocathode is obtained.The maximum QE reaches 13.0% at 290 nm.According to the t-mode QE equation solved from the diffusion equation,the QE curve is fitted.From the fitting results,the electron escape probability is 0.32,the back-interface recombination velocity is 5×104 cm·s-1,and the electron diffusion length is 116 nm.Based on these parameters,the influence of GaN thickness on t-mode QE is simulated.The simulation shows that the optimal thickness of GaN is 90 nm,which is better than the 150-nm GaN.

A 150-nm-thick GaN photocathode with a Mg doping concentration of 1.6 × 10 17 cm -3 is activated by Cs / O in an ultrahigh vacuum chamber, and a quantum efficiency (QE) curve of the negative electron affinity transmission-mode (t- the QE curve was fitted to the t-mode QE equation solved from the diffusion equation, the QE curve is fitted. From the fitting results, the electron escape probability is 0.32 , the back-interface recombination velocity is 5 × 104 cm-s-1, and the electron diffusion length is 116 nm. Based on these parameters, the influence of GaN thickness on t-mode QE is simulated. The simulation shows that the optimal The thickness of GaN is 90 nm, which is better than the 150-nm GaN.