X-ray photoemission spectroscopic investigation of surface treatments, metal deposition, and electron accumulation on InN

The effects of surface chemical treatments and metal deposition on the InN surface are studied via synchrotron-based photoemission spectroscopy. Changes in the In 4d core level as well as the valence band spectra are reported. The surface Fermi level position, EF, relative to the valence band maximum was determined for both Au and Ti Schottky barriers. EF lies at an energy of 0.7 eV above the valence band maximum for Au deposited on annealed InN and 1.2 eV above the valence band maximum for Ti deposited on Ar-sputtered InN. These results that the surface Fermi level lays at or above the conduction band maximum when a value of InN band gap of 0.7–0.9 eV is assumed.