Band bending at the surfaces of In-rich InGaN alloys

Abstract

The band bending and carrier concentration profiles as a function of depth below the surface for oxidized InxGa1−xN alloys with a composition range of 0.39≤x≤1.00 are investigated using x-ray photoelectron, infrared reflection, and optical absorption spectroscopies, and solutions of Poisson’s equation within a modified Thomas–Fermi approximation. All of these InGaN samples exhibit downward band bending ranging from 0.19 to 0.66 eV and a high surface sheet charge density ranging from 5.0×1012 to 1.5×1013 cm−2. The downward band bending is more pronounced in the most In-rich InGaN samples, resulting in larger near-surface electron concentrations.