Cathodoluminescence study of nitride transistor structures characterisation of native oxide

Cathodoluminescence studies of GaN transistor structures have revealed a deep UV band at about 5 eV. The band was characterised as a function of accelerating voltage, temperature and spatially resolved images were taken. A similar band was detected in both undoped n-type and p-type doped GaN. We tentatively identify the band to be due to emission from the native gallium oxide.