Asymmetric Bipolar Injection in a Schottky-Metal/ ${p}$ -GaN/AlGaN/GaN Device Under Forward Bias

In this letter, we investigated the electroluminescence (EL) spectra and photovoltage spectrum of a Schottky-metal/p-GaN/AlGaN/GaN diode with a semitransparent anode electrode. By analyzing the bias-dependence of the EL spectra of the diode as well as the gate stress bias-/time-dependences of the threshold voltage shift of a p-GaN gate HEMT, the electron/hole injection sequence, electron trapping, hole-assisted de-trapping, and optical pumping processes in the p-GaN gate region are identified. The band diagrams of the Schottky-metal/p-GaN/AlGaN/GaN heterostructure under different forward bias voltages are proposed.