The defect structure of oxygen-doped GaN grown by MOVPE was investigated. At high oxygen pressures, a super-linear increase of electron concentration as a function of partial pressure was observed. Electron concentrations as high as 7 × 1019 cm-3 were measured. Formation of micropits was observed by scanning electron microscopy in heavily doped samples. Cross-sectional transmission electron microscopy studies indicated the presence of epitaxial precipitates located on the cavity surface. The precipitates are believed to be related to gallium oxide. Using spatially resolved photoluminescence (PL), a broad PL band at 3.56 eV was observed near the micropit regions. The band was attributed to free-electron recombination from the highly degenerate areas associated with oxygen.
- O-doped GaN
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering