Growth of a -plane GaN on lattice-matched ZnO substrates using a room-temperature buffer layer

Abstract

Nonpolar a -plane GaN films were grown on nearly lattice-matched a -plane ZnO substrates by pulsed laser deposition. Growth of GaN on a -plane ZnO at conventional growth temperatures (around 700 °C) resulted in the formation of polycrystalline materials, probably due to the interface reactions between GaN and ZnO. However, single crystalline a -plane GaN with an atomically flat surface can be grown on ZnO at room temperature in the layer-by-layer mode. X-ray diffraction and photoluminescence measurements revealed that high-quality a -plane GaN films can also be grown at elevated substrate temperatures (up to 700 °C) by using a RT a -plane GaN film as a buffer layer. © 2007 American Institute of Physics.