Monopole Charge Domain in High-Gain Gallium Arsenide Photoconductive Switches
Monopole Charge Domain in High-Gain Gallium Arsenide Photoconductive Switches
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DOI：
10.1088/0256-307x/19/8/327
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发表时间：
2002-08
影响因子：
3.5
通讯作者：
Shi Wei;Er-Zhu Chen;Xian-Bin Zhang;Li Qi
中科院分区：
文献类型：
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作者：
Shi Wei;Er-Zhu Chen;Xian-Bin Zhang;Li Qi
考虑到半绝缘砷化镓光电导开关可以被触发进入高增益模式，并且没有可靠的理论可以解释所观察到的瞬态特性，我们提出了一种新的电荷畴模型来解释高增益模式下发生的特殊开关现象，并讨论了锁定开关的要求。在此模式下工作期间，开关两端的外加磁场和锁定磁场均大于古恩阈值磁场。我们开发的双电荷畴是基于转移电子效应，但由于负微分迁移率，该畴仅由大量电子堆积而成。利用该模型，考虑雪崩碰撞电离和复合辐射的物理机制，解释了光照射开始到开关开启的时间延迟等锁定效应的典型现象，以及维持相的传导机制.在不同的偏置场强和入射光能量条件下，计算了开关的延迟时间。结果表明，发生在双电荷畴内的碰撞电离和复合辐射的物理机制是导致锁定开关的主要原因。
Considering that semi-insulating gallium arsenide photoconductive switches can be triggered into the high gain mode and no reliable theories can account for the observed transient characteristics, we propose the monopole charge domain model to explain the peculiar switching phenomena occurring in the high gain mode and we discuss the requirements for the lock-on switching. During operation on this mode, the applied field across the switch and the lock-on field are all larger than the Gunn threshold field. Our developed monopole charge domain is based on the transferred-electron effect, but the domain is only composed of large numbers of electrons piled up due to the negative differential mobility. Using the model and taking the physical mechanism of the avalanche impact ionization and recombination radiation into consideration, we interpret the typical phenomena of the lock-on effect, such as the time delay between the beginning of optical illumination and turning-on of the switch, and the conduction mechanism of the sustaining phase. Under different conditions of bias field intensity and incident light energy, the time delay of the switching is calculated. The results show that the physical mechanisms of impact ionization and recombination radiation occurring in the monopole charge domain are responsible for the lock-on switching.