GaAs光电阴极表面电子逸出概率与波长关系的研究  

Study of Relation between Surface Electron Escape Probability of GaAs Photocathode and Incident Photon Wavelength

作　　者：邹继军[1] 陈怀林[1] 常本康[1] 王世允[1] 

机构地区：[1]南京理工大学电子工程与光电技术学院

出　　处：《光学学报》2006年第9期1400-1403,共4页Acta Optica Sinica

基　　金：教育部高等学校博士点基金(20050288010);国防科技重点预研(404050501D)资助课题

摘　　要：GaAs光电阴极量子效率公式中用到的表面电子逸出概率,在阴极工作波段范围内通常视为与入射光子波长无关的常数。应用该结论对反射式GaAs光电阴极激活实验结果进行了拟合分析。实验采用分子束外延GaAs材料,外延发射层厚度为1.6μm、掺杂浓度为1×1019cm-3,分析结果显示理论曲线与实验曲线存在偏差,而在激活台内阴极灵敏度下降后的光谱响应曲线拟合结果偏差更大。这种偏差是由于表面电子逸出概率对入射光子波长的依赖关系造成的,并非通常认为的与波长无关。经过光谱响应曲线的拟合分析得出,反射式阴极表面电子逸出概率与入射光子波长之间近似满足指数关系,两者通过表面势垒因子相联系。高、低温激活后阴极表面势垒因子分别为3.53和1.36。Surface electron escape probability （P） in quantum efficiency formula of GaAs photocathode commonly is taken for a constant independent of incident photon wavelength （it） within photocathode working wave band. Quantum efficiency formula is applied in data fitting of spectral response curves of reflection-mode GaAs photocathode grown by molecular beam epitaxy, in which the epitaxial layer thickness is 1.6μm, and doping concentration is 1 ×10^19 cm^-3. Data fitting results show that theoretical curves cannot tally with experimental curves completely, especially with declined spectral response curves of photocathode in activation chamber. This deviation is caused by the relation of P and it, and P is not a constant independent of it. Based on the data fitting analysis of spectral response curves, it is found that the relation of P and it for reflection-mode photocathode approximately satisfies exponential function, and P connects with it through surface potential barrier factor （k）. Photocathode surface potential barrier factors after high- and low-temperature activation process are 3.53 and 1.36 respectively.

关 键 词：光电子学 指数函数 光谱响应 电子逸出概率 GAAS光电阴极 表面势垒因子 

分 类 号：TN223[电子电信—物理电子学]