The surface chemistry and electrical properties of p -type and n -type AlGaN surfaces were studied via x-ray photoelectron spectroscopy before and after oxidation and wet chemical treatments. Shifts in the surface Fermi level were measured with the change in onset of the valence-band spectra. Oxidation and HF and (N H4) 2 Sx treatments on p -type AlGaN (n -type AlGaN) led to an increase (the reduction) in the surface band bending due to more N vacancies and N vacancies being occupied by S (i.e., donorlike states) than Al vacancies and Ga vacancies (i.e., acceptorlike states) near the p -type AlGaN (n -type AlGaN) surface region. The changes in surface chemistry indicate that oxidation and wet chemical treatments alter the surface state density through the formation of more donorlike states.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)