Quantum efficiency of heterostructured AlN/AlxGa1-xN photocathodes with graded bandgap emission layer
Quantum efficiency of heterostructured AlN/AlxGa1-xN photocathodes with graded bandgap emission layer
复制标题
具有渐变带隙发射层的异质结构 AlN/AlxGa1-xN 光电阴极的量子效率
DOI：
10.1007/s10854-018-9361-0
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Liu Zhanhui
中科院分区：
文献类型：
--
作者：
Yang Mingzhu;Guo Jing;Fu Xiaoqian;Liu Zhanhui
为了提高AlGaN光电阴极的量子效率，提出了一种由蓝宝石衬底层、AlN缓冲层和渐变带隙发射层组成的异质结构AlN/AlxGa 1 −xN光电阴极。基于一维连续性方程，推导了透射式和反射式光电阴极的理论模型，分析了器件的特性。结果表明，发光层中的带隙梯度产生的多级内建电场，可以延长电子的扩散长度，降低背界面复合损耗，从而提高量子效率。讨论了光阴极厚度和子层中铝成分对效率的影响。该工作为进一步提高AlGaN光电阴极的性能提供了理论指导。
A heterostructured AlN/AlxGa1−xN photocathode consisting of a sapphire substrate layer, a AlN buffer layer, and a graded bandgap emission layer is proposed to improve the quantum efficiency of AlGaN photocathode. The theoretical models for transmission-mode and reflection-mode photocathodes were deduced based on one-dimensional continuity equations to analyze the characteristics of the devices. Results show that the multilevel built-in electric field induced by the bandgap gradation in the emission layer can improve the quantum efficiency because of the longer electron diffusion length and the reduction of the back-interface recombination losses. The effect of thicknesses of photocathodes and Al composition in the sublayers on efficiency is discussed. This work would provide theoretical guidance for better performance of AlGaN photocathodes.