Accumulation and depletion in InAs epilayers

Abstract

Thin heteroepitaxial layers of In0.8Al0.2As grown on InAs surfaces by molecular beam epitaxy can reduce the density of surface states which pin the Fermi level and cause surface accumulation. Biased capacitance-voltage and gated Hall measurements indicate that InAs surfaces can be driven through the flat-band into depletion with the density of surface states reduced to ~1.5 × 1012 cm-2 eV-1 below the Fermi level.