高掺杂N对金红石型TiO2电子结构和红移影响的理论研究

摘要

By adopting the ab-initio study of plane wave ultra-soft pseudo-potential technique based on the density function theory (DFT),we presented geometric structure optimizations,as well as calculations of band distribution,density of states and absorption spectrum,on heavily N-doped rutile TiO2 supercell models as well as nondoped TiO2 ones. Calculation results show that,when the concentration of N equals x＝0.0625, N 2p state and O 2p state hybrid couples together, causing valence band shifting up, minimum band gap narrowing,and absorption spectrum red shifting,which is consistent with similar effects in experiments on heavily N-doped TiO2.%采用密度泛函理论框架下的第一性原理平面波超软赝势方法,在相同环境条件下分别建立了未掺杂和取代O高掺杂N原子的金红石型TiO2超胞模型,优化了晶胞的几何结构,计算了能带分布、态密度分布和吸收光谱.结果表明,金红石型TiO2-xNx超胞取x=0.0625的条件下,N的2p态与O的2p态发生杂化耦合,使其价带上移、最小带隙变窄、吸收光谱发生红移现象,这和实验中高掺杂N原子Ti2-xNx带隙变窄红移现象相吻合.