Multiple charge domains model for the lock-on effect in GaAs power photoconductive switches
Multiple charge domains model for the lock-on effect in GaAs power photoconductive switches
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DOI：
10.1088/0022-3727/41/11/115107
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发表时间：
2008-06
期刊：
影响因子：
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通讯作者：
Liqiang Tian;W. Shi
中科院分区：
文献类型：
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作者：
Liqiang Tian;W. Shi
测量了半绝缘GaAs光电导开关在不同偏压下的锁定场。基于实验结果和转移电子效应，提出了GaAs光子晶体开关中的锁定效应模型。结果表明，电荷畴与一个负电场是由于一个高的光生载流子密度，这引起强烈的碰撞电离伴随着电子-空穴复合辐射的域内。由于吸收复合辐射产生的载流子可以不间断地使新畴成核，因此最前沿的畴以在光子速度和载流子饱和漂移速度之间交替的速度穿过开关，这使得观察到的载流子速度大于饱和漂移速度。锁定场是由雪崩电荷畴运动列的固定数目、稳态畴电场和畴外恒定电场共同作用的结果。锁定效应的恢复是由畴淬灭引起的。计算结果与实验结果一致。此外，分析结果表明，SI-GaAs PCSS本质上是一种光激活电荷畴器件。
This paper reports that the lock-on field of semi-insulating (SI) GaAs photoconductive semiconductor switches (PCSSs) was measured under different bias voltages. Based on the experimental results and the transferred-electron effect, a model for the lock-on effect in GaAs PCSSs is proposed. It is shown that the charge domain with an ultrahigh electric field is due to a high photogenerated carrier density, which gives rise to intensive impact ionization accompanied by electron–hole recombination radiation within the domain. Since new domains can be nucleated uninterruptedly by the carriers generated by absorption of recombination radiation, the forefront domain crosses the switch at a speed alternating between the photon velocity and the carrier saturated drift velocity, which makes the observed velocity of carriers larger than the saturated drift velocity. The lock-on field results from the fixed number of a moving train of avalanching charge domains, the steady-state domains electric fields and the steadfast external electric field of the domains. The recovery of the lock-on effect is caused by domain quenching. The calculations agree with the experimental results. Moreover, the analytical results indicate that SI-GaAs PCSS is essentially a type of photo-activated charge domain device.