摘要
通过求解一维稳态少数载流子扩散方程,推导了指数掺杂和均匀掺杂的透射式GaAs光电阴极表面光电压谱理论方程。利用金属有机化学气相沉积(MOCVD)外延生长了发射层厚度相同、掺杂结构不同的两款透射式阴极材料。通过表面光电压谱实验测试和理论拟合发现指数掺杂结构在发射层厚度和后界面复合速率相同的情况下能够有效提高阴极电子扩散长度,这主要由于内建电场能够促使光生电子通过扩散和电场漂移两种方式向表面运动,从而最终提升阴极的发射效率和表面光电压谱。利用能带计算公式和电子散射理论对这两种不同结构材料的表面光电压谱进行了详细分析。
By solving the one-dimensional diffusion equation for equilibrium minority carriers of transmission-mode GaAs phtotocathodes, the equations for surface photovoltage spectroscopy of exponential and uniform doping transmission-mode GaAs photocathodes are deduced. Through metal organic chemistry vaporation deposition （MOCVD） technique, two GaAs photocathodes of different doping structures with the same active layer depth are designed. By measuring and theoretically emulating the surface photovoltage spectroscopy curves for two materials, the exponential doping structure can well increase the electric diffusion length for transmissionimode GaAs photocathodes. The reason is that the internal electric field can drive the photo-excited electrons to move toward surface barriers through both diffusing and electric field drifting, thus can finally elevate the emission efficiency and the surface photovoltage spectroscopy. The difference of two surface photovoltage spectroscopy waves can be well explained by the internal energy band equations and electron scattering theory.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2011年第9期138-142,共5页
Chinese Journal of Lasers
基金
国家自然科学基金(60678043
60801036)
国家质检总局项目(2008QK328)资助课题
关键词
光电子学
GAAS光电阴极
表面光电压谱
电子扩散长度
optoelectronics
GaAs photocathode
surface photovoltage spectroscopy
electron diffusion length
