Probing the Electronic Structure of Chalcogen Ultra-doped Silicon

Chalcogen impurity atoms in silicon have been shown to introduce deep energy levels within the bandgap. Absorption coupled to these defect levels could account for the enhanced sub-bandgap absorption. We will report on the methods and preliminary results of measuring the absorption coefficient in the isolated S-doped layer. Additionally, we use x-ray spectroscopy to probe the electronic properties of the material, and to understand the specific role that dopant states play in enhanced absorption.