Charge transfer across the As/Si(100)-2×1 interface

A high-performance Auger spectrometer has been used to separate the bulk and interface contributions to the Auger spectra of the As/Si(100) interface. Combining these results with measurements of the photoelectron spectra of core levels shows that the Auger-parameter shifts between atoms at the interface and in the bulk elements are -0.64\ifmmode\pm\else\textpm\fi{}0.04 eV for As and 0.68\ifmmode\pm\else\textpm\fi{}0.04 eV for Si. The Auger-parameter shifts are analyzed in terms of recent theoretical models that indicate that there is a small charge transfer of \ensuremath{\sim}0.2e from Si to As at the interface.