Electroluminescence from n-ZnO : Ga/p-GaN heterojunction light-emitting diodes with different interfacial layers

Abstract n-ZnO : Ga/p-GaN heterojunction light-emitting diodes with different interfacial layers are fabricated by pulsed laser deposition. All the devices demonstrate nonlinear rectifying behaviour. Due to the formation of Ga2O3 interfacial layers, n-ZnO : Ga/p-GaN exhibits strong ultraviolet emission centred at 382 nm and blue emission centred at 423 nm. Compared with a n-ZnO : Ga/MgO/p-GaN light-emitting diode, the turn-on voltage of n-ZnO : Ga/p-GaN with a Ga2O3 interfacial layer drops down to 7.6 V and the ultraviolet emission intensity is enhanced. Detailed electroluminescence mechanisms influenced by the interfacial layer are discussed using the band diagram of heterojunctions.