Charge transfer and electronic activation at an Sb δ-layer in Si(001)

Thin sheets of dopant atoms (δ-layers) have been shown to give unprecedented microscopic control over interfaces between semiconductors, though there exists very little understanding of the fundamental changes in the electronic structure in the vicinity of the δ-doped layer. Recent work in electron spectroscopy has shown that the combination of environmentally determined photoelectron and Auger electron shifts within the Auger parameter can provide insight into the differences in local electron screening and charge transfer. In this work, we apply the technique to the study of Sb δ-layers in epitaxially grown Si(001) and have been able to determine for the first time using spectroscopic techniques the existence of two different environments for Sb in Si, and that only 17% of the donor atoms are electrically active.