Deposition of high quality wurtzite GaN films over cubic (111) MgAl2O4 substrates using low pressure metalorganic chemical vapor deposition

We report the deposition of high quality single-crystal wurtzite GaN films on cubic (111) spinel (MgAl2O4) substrates. The room-temperature electron mobility and the optically pumped stimulated emission threshold for these films are nearly identical to those of films deposited on basal plane sapphire. Using cross sectional high resolution TEM we have determined the following orientation relationship between the film and the substrate: [0001]GaN//[111]MgAl2O4 and [112̄0]GaN//[110]MgAl2O4. This should provide a common cleavage plane for (111) spinel and the wurtzite GaN films over it.