Investigation of the Effect of Oxygen on the Near-Surface Electron Accumulation in Nonpolarm-Plane (101̄0) InN Film by Hard X-ray Photoelectron Spectroscopy

A strong electron accumulation was observed in a near-surface region of an as-grown nonpolar m-plane (100) InN film by analyzing the valence band hard X-ray photoelectron spectra as a function of the take-off angle. In addition, two oxygen chemical states correlated with electron carrier concentration were observed in the O 1s core-level spectra. By comparing with the oxygen concentration in a bulk-like region, the amount of oxygen drastically increased in a near-surface region, suggesting that the oxygen atoms in the near-surface region act as donors to contribute to the near-surface electron accumulation layer.