Electron energy loss spectroscopy applied to semiconductor space charge layers

Abstract

The application of high resolution electron energy loss spectroscopy (HREELS) to the study of space charge layers including Schottky barriers at semiconductor interfaces is discussed. The basic concept of the technique consists in probing the free carrier interface plasmon or plasmon-phonon polariton by means of inelastic electron scattering. Spectral positions and halfwidth of the corresponding loss bands give information about space charge layer parameters as space charge concentration, barrier height, transport parameters etc. Beside the classical example of the depletion layer on GaAs(110), the Schottky barrier at the lnSb(110) -Sn interface and the space charge layer on the clean Si(100) surface are considered. Recent theoretical studies show that even more detailed information about interface potential barriers (spatial dependence of space charge, fields etc.) can be obtained by applying HREELS measurements with high angular resolution.