Ultraviolet and visible electroluminescence from n-ZnO/SiOx/(n,p)-Si heterostructured light-emitting diodes

n-ZnO/SiOx/n-Si and n-ZnO/SiOx/p-Si heterostructured light-emitting diodes have been fabricated using metal-organic chemical-vapor deposition for a comparison study. n-ZnO/SiOx/p-Si heterostructures show diodelike rectifying current-voltage characteristic with low breakdown voltage, while n-ZnO/SiOx/n-Si heterostructures show symmetric nonlinear current-voltage behavior due to the double Schottky barriers at the interface. Both types of diodes emit light when a positive bias applied at Si side. Ultraviolet emission at similar to 390 nm with an orange-emission centered at similar to 600 nm were observed in electroluminescence spectra of n-ZnO/SiOx/n-Si diodes, while whitish emission centered at similar to 520 nm was observed for n-ZnO/SiOx/p-Si diodes. The emission mechanisms were discussed. (C) 2008 American Institute Of Physics.