Effect of the AlN interlayer on electroluminescent performance of n-SnO2/p-GaN heterojunction light-emitting diodes

Light emitting diodes (LEDs) based on n-SnO2/p-GaN heterojunction were fabricated by pulsed laser deposition (PLD). The effects of post-annealing treatment and interfacial layers on electroluminescence (EL) of n-SnO2/pGaN were investigated. After annealing in vacuum, all the LED devices with different interfacial layers exhibit a nonlinear current-voltage behavior. The SnO2/p-GaN light emitting diodes exhibit two emission peaks, a violet peak (410 nm) and the broad yellow-orange emission band (600-700 nm), whereas only the yellow-orange EL spectra could be found in the SnO2/AlN/p-GaN. Using the band diagram, the carrier blocking process by different interfacial layer and the electroluminescence mechanisms of heterojunction LEDs were discussed in detail.