Electronic structure and optical properties of B/P-doped amorphous Si calculated by first-principles

In order to understand the electronic structures, optical properties, and explain the experimental observations of B/P-doped amorphous Si, the relevant micro-structure and properties have been calculated by simulated annealing and DFT+U methods. Based on the calculated results, the short-range order features of micro-structure in amorphous Si lead to the similar electronic structure and optical properties with crystalline Si, owing to the short-range order reflects the nature of atomic chemical bonding and plays a major role in the decision of fundamental characteristics of amorphous Si. What is important, the long-range disorder features of micro-structure lead to the different electronic structure and optical properties of amorphous Si, in compared with crystalline Si. Especially, the localized states caused by structural defects predominately determined the optical properties in visible-light region. The findings in the present work could well explain the experimental observations in literatures, and are helpful for the development of amorphous Si based functional materials.