High-resistivity GaN homoepitaxial layer studied by Schottky diode structure

An undoped GaN homoepitaxial layer has been grown by metal-organic chemical vapour deposition on a conductive free-standing bulk GaN substrate. The dislocation density of the homoepitaxial layer characterised by cathodoluminescence mapping technique is about 6 times 10⁶ cm^-2. By fabricating a vertical Schottky diode structure, the resistivity of the homoepitaxial layer is estimated in the order of 10⁹ cm at room temperature. This study indicates that highly-resistive GaN can be produced by a homoepitaxy approach.