Structure of Chemically Passivated Semiconductor Surfaces Determined Using X-Ray Absorption Spectroscopy

The structure of monolayer-passivated single crystal semiconductor surfaces has been studied using synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS). The near edge and extended fine structure signals, supported in some cases by first-principles calculations, have been used to investigate Ge(111)-Cl; GaAs(111)-Cl; GaAs(111)A-S, GaAs(111)B-S and GaAs(001)-S. The use of a solid state Ge X-ray fluorescence array detector has led to significant improvements in data quality and thus structural accuracy. The relationship between the derived surface structures and the development of improved passivated surfaces is discussed.