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

Abstract

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+0.04 eV for As and 0.68+0.04 eV for Si. The Augerparameter shifts are analyzed in terms of recent theoretical models that indicate that there is a small charge transfer of -0.2e from Si to As at the interface.

An experimental study of charge distribution in crystalline and amorphous Si nanoclusters in thin silica films

“…͑5͒ and the values are shown in Table III 41 More specifically, a negative ⌬␤ value is associated with a negative shift of the potential ͑⌬V͒. 17,24 In the above context, the decrease in initial state Auger parameter ͑␤͒ of the amorphous nanoclusters indicates an increased accumulation of negative charge as compared to the crystalline nanoclusters.…”

“…Interpretations of XPS spectra are often based on shifts of peak positions and Auger parameters. 17,18 The peak shift between two different chemical environments is known as a chemical shift and is defined as the binding energy difference ͑⌬E B ͒ between atoms bonded to different chemical species, e.g., elemental Si and SiO 2 ͑E B Si 4+ -E B Si 0 ͒. However, the determination of chemical shifts depends on reliable measurements of XPS peak positions, which in turn are sensitive to energy referencing issues.…”

“…͑1͒-͑3͒ leads to two different Auger parameter expressions reflecting either initial or final state effects; the initial 17 ͑⌬␤͒ and final state 20,21 ͑⌬␣͒ Auger parameter, respectively,…”

“…In addition, chemical shifts ͑in the form of binding or kinetic energy differences͒ contain both initial and final state contributions, as shown by Eqs. ͑1͒ and ͑2͒ below, 17 ⌬E B ϳ ⌬V + ⌬ − ⌬R ͑1͒…”

The Development of Auger Spectroscopy as a Probe of Local Electronic Structure

“…By employing X-ray excitation and measuring XPS and Auger spectra simultaneously Aa can be measured accurately and to a first approximation it gives a direct determination of the environmentally induced differences in the final state screening contribution to the energy associated with the creation of a core-hole [29]. For this reason Aa has been termed the final state Auger parameter in recent work [30][31][32] in order to distinguish it from another way of combining (1) and (2) [4,27,34] to relate the potential in an atomic core to the atomic valence charge;…”