Correlation of GaAs surface chemistry and interface Fermi-level position: A single defect model interpretation

Abstract

XPS measurements of core-level binding energies have been used to determine the interface Fermi-level position in (100) and (110) n-and p-type GaAs samples as a function of surface treatment. A variation in interface Fermi-level position of up to 0.7 eV has been observed. The difference in interface Fermi-level position for n- and p-type samples subjected to identical surface treatments remains nearly constant at ≊0.3 eV. A single defect model (SDM) is suggested which appears to provide the simplest explanation for the observed interface-potential variations.