First principle study of electronic structures and optical properties of Ce-doped SiO2

Wei-Yan Cong,Cheng-Bo Guan,Peng Zhang,Ying-Bo Lu

doi:10.1063/1.5024592

Abstract

Electronic structures and optical properties of Silicon dioxide (SiO2) systems with and without cerium(Ce) dopant were calculated using the density functional theory. We find that after the Ce incorporation, a new localized impurity band appears between the valance band maximum (VBM) and the conduction band minimum (CBM) of SiO2 system, which is induced mainly by the Ce-4f orbitals. The localized impurity band constructs a bridge between the valence band and the conduction band, making the electronic transition much easier. The calculated optical properties show that in contrast from the pure SiO2 sample, absorption in the visible-light region is found in Ce-doped SiO2 system, which originates from the transition between the valence band and Ce-4f dominated impurity band, as well as the electronic transition from Ce-4f states to Ce-5d states. All calculated results indicate that Ce doping is an effective strategy to improve the optical performance of SiO2 sample, which is in agreement with the experimental results.

Highlights

Silicon dioxide (SiO2) material is widely used in the fields of catalyzer carrier, medium layer and silicon-based optoelectronic integration for its excellent chemical stability, thermal stability, insulation, and good interfacial combination with silicon semiconductors.[1]
All calculations are performed within the projector augmented wave (PAW)[22] methods implemented in the CASTEP code,[23] which is based on the density functional theory.[24]
According to the total and partial density of states (PDOS) shown in Fig. 2(b), we find that the valence band is mainly contributed by the hybridization of O-2p states and Si-3p states

Summary

Introduction

Silicon dioxide (SiO2) material is widely used in the fields of catalyzer carrier, medium layer and silicon-based optoelectronic integration for its excellent chemical stability, thermal stability, insulation, and good interfacial combination with silicon semiconductors.[1]. Because of the wide bandgap, SiO2 could not emit visible-light efficiently, which limits its efficient application for luminescent device. Many approaches have been attempted to overcome the obstacle and achieve efficient emission from SiO2. One of the most promising solutions is to introduce impurities such as rare-earth elements into SiO2 materials.[2,3,4,5,6,7] For instance, Li et al implanted Ce and Tb ions into silicon oxides films and obtained visible-light emissions.[8] O. M. Ntwaeaborwa et al reported that various emissions in visible-light region can be obtained in cerium (Ce)- europium (Eu) codoped SiO2 samples.[2]

Methods

Results

Conclusion