In Situ Surface State Spectroscopy by Photoluminescence and Surface Current Transport for Compound Semiconductors

By a rigorous computer analysis of the surface recombination process, it is shown that the surface state distributions on semiconductor free surfaces can be determined from a measurement of the dependence of band-edge photoluminescence intensity on the excitation intensity. The measurement of the Fermi level pinning position in the dark by the surface current transport measurement avoids the possible ambiguity of the interpretation. The new technique is successfully applied to variously treated GaAs surfaces and to passivated InGaAs surfaces with and without the ultrathin Si interface control layer.