Photocurrents in GaN-based HEMTs: Theoretical model and experimental results

An experimentally validated model for persistent photocurrents (PPC) in GaN HEMTs has been presented, which can explain both the build-up and decay course. Compared to the popular stretched exponential fit, it employed parameters with a clear physical meaning and could give numerical solutions to predict and support the experimental results. In particular, the effect of the electric field on the photocurrents was found to be closely linked to the probability of the electron-hole recombination used in this model, which provides a way to study the influence of the electric field on PPC. This experimentally verified model with clear and meaningful parameters could be used to better understand the PPC in GaN-based HEMTs.