Numerical Studies into the Possibility of "Lock-On" in a GaN Photoconductive Switch for High Power Applications

Time-dependent photocurrent response in semi-insulating GaN is simulated with a focus on the Lock-On phenomenon. A one-dimensional, time-dependent model based on the drift-diffusion theory is used. The model is tested for GaAs and shown to yield good agreement with data. The GaN simulations are then performed. The main findings are that deeper traps nearer the valence band at higher densities, and materials with larger high-field drift velocity would all aid in attaining Lock-On. The threshold field for Lock-on in GaN is predicted to be around 150 kV/cm, though this is strongly dependent on the trap parameters.