砷化镓中广延缺陷的光致发光研究  

Photoluminescence of Extended Defect in GaAs

作　　者：吕恒 胡昌奎[1] LYU Heng;HU Chang-kui(School of Science,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学理学院,武汉430070

出　　处：《人工晶体学报》2018年第8期1529-1534,共6页Journal of Synthetic Crystals

基　　金：国家自然科学基金(51702245)

摘　　要：采用大视场光致发光和电致发光实时光谱成像快速检测Ga In P/GaAs/Ga In P双异质结样品及太阳能电池器件GaAs层中孤立的广延缺陷,并运用不同激光功率对样品进行激发,基于广延缺陷的空间分辨光致发光光谱成像行为探讨了砷化镓中载流子的扩散特性。实验结果表明,当激发光功率密度较小时,由于激发点附近点缺陷的非辐射复合竞争降低了光生载流子的平均寿命,从而使得扩散长度急剧减小。只有当激发光功率密度超过一个阈值使得点缺陷态饱和后,载流子的长距离扩散才能变为可能。此外,根据光激发一维扩散模型求解扩散方程得出对比函数的指数表达形式,并由广延缺陷区域光致发光强度的径向分布导出对比函数值,通过函数拟合估算出砷化镓样品的有效扩散长度。A large field of view PL imaging system or EL imaging system was used to first identify the individual extended defect in two different samples with GaInP/GaAs/GaInP double heterostructures.The samples were excited by different laser power,and the diffusion characteristics of the carrier in GaAs were discussed based on the spatial resolved PL mapping of the extended defect.It shows that the effective diffusion length of carriers changes with the excitation power density by photoluminescence measurement.When the excitation power density is very small,the concentration of photo-generated carrier is very low,and the nonradiative recombination of point defects will reduce the average lifetime of carriers and decrease the effective diffusion length.It can be possible for the carriers to achieve the long distance diffusion only when the point defect state is saturated.In addition,based on the one-dimensional diffusion model of photo-excited carrier,the expression of the contrast function is obtained by solving the diffusion equation.The corresponding value of the contrast function is calculated from the radial distribution of the photoluminescence intensity near the extended defect,and then the effective diffusion length of the samples is derived through data fitting.

关 键 词：砷化镓 广延缺陷 光致发光 

分 类 号：O474[理学—半导体物理]