Lower Bound of Electrical Field for Maintaining a GaAs Photoconductive Semiconductor Switch in High-Gain Operating Mode

The high-gain operating mode of gallium arsenide (GaAs) photoconductive semiconductor switch (PCSS) brings the hope that a higher power PCSS will be triggered by a lower energy laser. However, the lock-on effect of high-gain PCSS restricts its lifetime and some other applications. In this paper, it is experimentally demonstrated that dynamically controlling the electrical field across a GaAs:EL2 PCSS can terminate the carrier avalanche and that there exists a lower bound of electrical field (about 3.64 kV/cm) for maintaining the high-gain operating mode of the PCSS under different conditions. This lower bound of electrical field is approximately equal to that of the transferred-electron effect; hence, it supports the hypothesis of a photon-activated charge domain to explain the physical phenomena of the high-gain PCSS.