Dependence of electron accumulation in AlSb/InAs quantum well on thin surface materials of InAs and GaSb

The role of thin surface material in electron accumulation of an AlSb/InAs quantum-well system is reported. Electron density transferred from surface to well is much smaller when InAs was grown at the surface than when GaSb was grown at the surface. This result is explained by the difference of surface pinning positions between InAs and GaSb. The surface pinning position of InAs is obtained to be lower by 0.2 eV than that of GaSb.