532 nm响应增强的AlGaAs光电阴极  

AlGaAs photocathode with enhanced response at 532 nm

作　　者：王东智 张益军[1] 李诗曼 童泽昊 唐嵩 石峰 焦岗成 程宏昌 富容国[1] 钱芸生[1] 曾玉刚[3] Wang Dong-Zhi;Zhang Yi-Jun;Li Shi-Man;Tong Ze-Hao;Tang Song;Shi Feng;Jiao Gang-Cheng;Cheng Hong-Chang;Fu Rong-Guo;Qian Yun-Sheng;Zeng Yu-Gang(School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;Science and Technology on Low-Light-Level Night Vison Laboratory,Xi’an 710065,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)

机构地区：[1]南京理工大学电子工程与光电技术学院,南京210094 [2]微光夜视技术重点实验室,西安710065 [3]中国科学院长春光学精密机械与物理研究所,长春130033

出　　处：《物理学报》2024年第11期368-376,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62271259,U2141239);微光夜视技术重点实验室基金(批准号:J20220102);江苏省研究生科研与实践创新计划(批准号:KYCX23_0431)资助的课题。

摘　　要：AlGaAs光电阴极具有响应速度快和光谱响应范围可调的特性,可被应用于水下光通信领域.为了解决AlGaAs发射层较低的光吸收限制其量子效率提高的问题,利用分布式布拉格反射镜(DBR)结构对特定波长光的反射作用,将透过光重新反射回发射层进一步提高吸收率,从而增强阴极在532 nm波长处的响应能力.通过求解一维连续性方程,建立了具有DBR结构的AlGaAs光电阴极光谱响应模型.采用时域有限差分法,分析了DBR结构中子层周期对数、子层材料以及发射层、缓冲层厚度对发射层吸收率的影响,对比了有无DBR结构AlGaAs光电阴极的光吸收分布.结果表明,周期对数为20、子层材料为Al_(0.7)Ga_(0.3)As/AlAs的DBR结构对532 nm光的反射效果最优.基于该DBR结构,发射层和缓冲层厚度分别为495 nm和50 nm时,发射层对532 nm光具有最佳吸收率.通过对外延生长的AlGaAs光电阴极进行激活实验,结果表明具有DBR结构的AlGaAs光电阴极在532 nm波长处的光谱响应率相比无DBR结构的AlGaAs光电阴极光谱响应率提升了约1倍.The AlGaAs photocathode can be used in the field of underwater optical communication because of its fast response speed and adjustable spectral response range.In order to solve the problem that the low light absorption of the AlGaAs emission layer limits the improvement of its quantum efficiency,the distributed Bragg reflector(DBR)structure is used to reflect the light at a specific wavelength back to the emission layer to further increase the absorption rate,thus improving the response capability of the photocathode at 532 nm.The spectral response model of the AlGaAs photocathode with DBR structure is obtained by solving one-dimensional continuity equation.The optical model of the AlGaAs photocathode with enhanced response at 532 nm is established by the finite-difference time-domain method.The effects of the sublayer periodic pairs,the sublayer material and the thickness of emission layer and buffer layer on the absorption rate of emission layer are analyzed.The light absorption distributions of AlGaAs photocathode with and without DBR structure are compared,and the influence mechanism of DBR structure on the blue-green light absorption capacity of AlGaAs photocathode emission layer is clarified,which can provide a theoretical basis for designing its structural parameters.The results show that the DBR structure with a periodic pair of 20 and Al0.7Ga0.3As/AlAs has the best reflection effect on 532 nm light.Based on the DBR structure,when the thickness of the emission layer and buffer layer are 495 nm and 50 nm,respectively,the emission layer has the best absorption rate of 532 nm light.Furthermore,two kinds of AlGaAs photocathodes with and without DBR structure are prepared by the metal-organic chemical vapor deposition technology,and the reflectivity and profile structure of the grown samples are characterized.Then the Cs/O activation experiments are performed to compare the spectral response curves.It is found that the spectral response of the AlGaAs photocathode sample with DBR structure at 532 nm wavelength

关 键 词：AlGaAs光电阴极 分布式布拉格反射镜 光谱响应 光吸收 

分 类 号：TN2[电子电信—物理电子学]