High-Integrated-Photosensitivity Negative-Electron-Affinity GaAs Photocathodes with Multilayer Be-Doping Structures  

高积分光电灵敏度多层Be浓度掺杂的GaAs负电子亲和势光电阴极(英文)

作　　者：王晓峰[1] 曾一平[1] 王保强[1] 朱占平[1] 杜晓晴[2] 李敏[2] 常本康[2] 

机构地区：[1]中国科学院半导体研究所,北京100083 [2]南京理工大学电子工程与光电子技术学院,南京210094

出　　处：《Journal of Semiconductors》2005年第9期1692-1698,共7页半导体学报（英文版）

摘　　要：The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.研究了变掺杂浓度结构对GaAs负电子亲和势光电阴极积分光电灵敏度的影响.通过MBE生长了两组GaAs同质外延样品.其中一组采用了均匀掺杂的单层结构,Be掺杂浓度为1×1019cm-3;另一组采用了变掺杂的多层结构,从衬底开始Be的掺杂浓度依次为1×1019,7×1018,4×1018和1×1018cm-3.负电子亲和势光电阴极通过在高真空系统中交替通入Cs和O激活得到.在线光谱响应测试曲线表明,多层Be掺杂结构光阴极的积分光电灵敏度比单层Be掺杂结构光阴极的积分光电灵敏度至少提高了50%.两种结构的GaAs样品表现出不同的表面应力情况.

关 键 词：integrated photosensitivity muhilayer structure NEA photocathode diffusion length surface escape probability 

分 类 号：TN304[电子电信—物理电子学]