砷化镓光导开关中电流丝的自发辐射效应

Spontaneous radiation effects of the current filament in GaAs photoconductive semiconductor switches

应用统计物理方法研究了高增益砷化镓光导开关中电流丝的自发辐射效应.导出了高增益砷化镓光导开关中电流丝的自发辐射规律,在砷化镓样品中引入复合辐射强度与辐射的波长分布函数的概念,近似确定了高增益砷化镓光导开关中电流丝的平均辐射复合系数为(883 nm)≈0.1125,导出了各辐射波长的辐射复合系数与平均辐射复合系数之间的关系,验证了峰值波长为890 nm的光输出能量与实验观察结果吻合,在理论上揭示了电流丝顶部的光生载流子密度的分布规律.结果表明:电流丝的体积面积比值和电流丝内平均载流子密度是影响电流丝辐射效应的两个主要因素,波长876 nm的辐射在紧邻电流丝顶部产生的最大载流子密度具有主导作用,最大光生载流子密度比电流丝内平均载流子密度小1–2个数量级.

The spontaneous radiation effects of current filament in high gain gallium arsenide （GaAs） photoconductive semiconductor switches （PCSS） have been studied by using the statistical-physical method. The spontaneous radiation law of the current filament in high gain GaAs PCSS was derived. In GaAs samples the concepts for the wavelength distribution function of the radiation intensity were introduced. The average radiative recombination coefficient of the current filament in high gain GaAs PCSS, η（883 nm）≈ 0.1125, was approximately determined. The relationship between radiative recombination coefficients of different radiation wavelengths and the average radiative recombination coefficient was deduced. It was verified that the optical output energy of the peak wavelength, 2=890 nm, coincided with the experimental observations. The density distribution of the carrier from the recombination radiation at the tip of the filament is revealed in theory. The results show the ratio of volume to area of the current filament and the average carrier density inside the current filament are two primary factors that affect the radiation effect of current filament. Reabsorption of λ≤876 nm radiations plays a dominant role for the maximum density of carrier from the recombination radiation. The maximum density of carrier from the recombination radiation at the tip of the filament is approximately 1-2 orders of magnitude lower than the average carrier density inside the current filament.