Schottky-on-heterojunction optoelectronic functional devices realized on AlGaN/GaN-on-Si platform

We demonstrated that the metal-AlGaN/GaN Schottky diode is capable of producing GaN band-edge ultraviolet (UV) emission at 3.4 eV/364 nm under forward bias larger than ∼2 V at room temperature. The underlying mechanism of the hole generation/injection and electroluminescence (EL) processes in this Schottky-on-heterojunction light-emitting diode (SoH-LED) was discussed based on the impact ionization of surface states presented in the (Al)GaN barrier layer. By replacing the conventional ohmic drain with a semitransparent Schottky drain, we demonstrated an AlGaN/GaN high-electron-mobility light-emitting transistor (HEM-LET) in which the drain current and EL emission are controlled simultaneously by gate voltage. Switching operation up to 120 MHz was obtained in SoH-LED to demonstrate its potential in providing high-speed on-chip light sources on the GaN electronic device platform.