Anomalous downward band bending induced by selenium passivation of MBE-grown InAs(001) surfaces

Abstract

In-situ synchrotron radiation photoelectron spectroscopy is used to study the surface chemical bonding structures on InAs(001) with and without Se passivation and to determine changes in the surface Fermi level ( E F) position as a result of Se treatment. Analysis of the As 3d and In 4d core-levels for the epitaxially grown InAs and reflection high-energy electron diffraction pattern observations are found to be almost the same as those for GaAs(001)-(2 × 4), showing that a well-ordered InAs(001)-(2 × 4) surface is achieved. The results of As 3d and In 4d spectra for the Se-passivated InAs show that a Se-terminated surface is formed where the topmost Se atoms bond to In. Anomalous downward band bending, where the E F position is located at about 0.5 eV above the conduction band minimum, is observed for the first time at the Se-passivated InAs(001)-(2 × 1), in contrast to the well-known results for Se-passivated GaAs.