Structural and Optical Properties of Point Defects in α-SiO2 Cluster* *Supported by the National Basic Research Program of China (973 Program) under Grant No. 2014CB643900, the Open Fund of IPOC (BUPT), the Open Program of State Key Laboratory of Functional Materials for Informatics, and the National Natural Science Foundation of China under Grant No. 61440061

Abstract

First-principles methods based on the density functional theory (DFT) are used in order to calculate the structural and optical properties of α-SiO2 cluster with the non-bridging oxygen hole centers (NBOHC) and NBOHC-E' defects. We clarify the stable structure of the NBOHC-E' point defects for the first time using the functional B3LYP, which is also tested to investigate the influence of electronic properties. The calculation is carried out for cluster configurations extracted from supercell. The results of optical absorption peak for Si2O7H6 and Si5O16H12 with NBOHC-E' defects are found at 2.66 eV, which is higher than the often observed OA peak at 2.0 eV for the NBOHC defect in α-SiO2. The overall absorption spectra are in qualitative agreement with the experiment.