Insulating GaN epilayers co-doped with iron and carbon

The morphology and electrical properties of doped semi-insulating gallium nitride (GaN) epilayers have been studied. It was found that doping-induced improvement of the insulating properties of GaN epilayers with increased level of doping with carbon or iron is limited by the accompanying deterioration of surface morphology. The character of impurity-related morphology development is different for the two dopants. It is established that the co-doping with carbon and iron allows planarity of the GaN surface to be retained along with a significant improvement of insulating properties of epilayers.