Sulfur passivation of surface electrons in highly Mg-doped InN

Electron accumulation with a sheet density greater than 1013 cm−2 usually occurs at InN surfaces. Here, the effects of treatment with ammonium sulfide ((NH4)2Sx) on the surface electronic properties of highly Mg-doped InN (>4×1018 cm−3) have been investigated with high resolution x-ray photoemission spectroscopy. The valence band photoemission spectra show that the surface Fermi level decreases by approximately 0.08 eV with (NH4)2Sx treatment, resulting in a decrease of the downward band bending and up to a 70% reduction in the surface electron sheet density.