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研究了光致电离在高增益本征砷化镓(GaAs)光导开关(PCSS)中的效应。在高增益本征砷化镓光导开关中,各级流注发展由三个过程组成:光致电离、畴电子崩(DEA)和载流子碰撞电离雪崩生长。光致电离在本征砷化镓绝缘区中产生局部高载流子密度区域,提供了允许畴存在的局域环境。光致电离包括激光触发和流注的复合辐射两种情形。分析了光导开关的最优触发激光条件。通过计算机数值模拟,计算了在距离流注表面y≤30μm的范围内,平均光生载流子密度n(t=0)乘以该局域的特征尺度满足偶极畴成核条件:n(t=0)·y>10~(12)cm~(-2);探讨了流注的复合辐射在流注周围产生非平衡载流子的规律;发现了触发区域沿电场方向的长度阈值L_(EC),触发区域的特征长度L_(E)必须满足条件:L_(E)≥L_(EC)。
The effect of photoionization on high gain intrinsic GaAs photoconductive switches (PCSS) was investigated. In high-gain intrinsic GaAs photoconductive switches, the development of flow injection at all stages consists of three processes: photoionization, domain electron collapse (DEA) and carrier-atom ionization avalanche growth. Photoionization generates localized high carrier density regions in the intrinsic gallium arsenide insulating region, providing a localized environment that allows domains to be present. Photoionization includes both laser-triggered and streamed composite radiation. The optimal triggering laser condition of the light guide switch is analyzed. By computer numerical simulation, we calculated that the average photo-generated carrier density n (t = 0) multiplied by the characteristic scale of this local area satisfies the condition of dipole domain nucleation in the range of y≤30μm from the surface of the streamer: n (t = 0) · y> 10 ~ (12) cm ~ (-2). The regularity of the nonuniform charge carrier generation around the stream is discussed. The length of the triggering region along the electric field is found to be L_ ( EC), the characteristic length L_ (E) of the trigger region must satisfy the condition: L_ (E) ≥L_ (EC).