Linking the Atomic and Electronic Structure of Amorphous Silicon Rings

Amorphous solids are highly amenable to property tuning because their atomic structures depend statistically on the specific details of the fabrication process. Amorphous Silicon (a-Si) is an important example due to its use in solar cells, computer chips, and many other technologies. Directing the development of advanced functional properties in a-Si depends heavily on the ability of theoretical models to accurately describe the complicated structure / function relationship derived from the atomic and electronic configuration. Therefore, this work uses first-principles density functional theory (DFT) calculations to systematically investigate the link between the atomic and electronic structure of ring features in a model of a-Si. The DFT-based orthogonalized linear combination of atomic orbitals method (OLCAO) method is used to compute bond strength and charge transfer statistics following the Mulliken scheme. The results are then mapped onto the statistical distribution of ring structures. The combined statistical data on n-membered rings and bonding properties are then related to the overall system properties to paint a clearer picture of the bulk structure/function relationship to support speculation on approaches that may be used to drive further tuning.