A GaN-Based LED With Perpendicular Structure Fabricated on a ZnO Substrate by MOCVD

A perpendicular InGaN/GaN multiple-quantum- wells structure on ZnO substrate for blue light emitting diode (LED) was successfully fabricated by use of Metal-organic Chemical Vapor Deposition (MOCVD). During the growing process of GaN-based materials on ZnO substrates, the low-temperature-grown GaN buffer layer, inserted between ZnO substrate and undoped GaN layer, prevented the Zn and O from diffusing from ZnO substrate into the n-GaN layer. This thin GaN buffer layer, mainly as a insulating layer, was grown at relatively low temperature of 530 °C. By using our method, an integrated LED with ZnO substrate can be fabricated with a crack-free GaN film on (0001) ZnO substrate by MOCVD using this method. The epilayer crystalline structure has been measured by atomic force microscopy (AFM), and the optical properties of the LED were also characterized by photoluminescence and Current-Voltage characteristic curve.