C掺杂对NaNbO_3材料性质影响的原理研究

Effect of C Doping on the Electronic Structure and Optical Properties of NaNbO_3:A First Principle Study

采用基于密度泛函理论的原理方法研究了纯NaNbO3和C掺杂NaNbO3的能带结构、态密度与吸收光谱。计算结果表明纯NaNbO3的价带主要由O 2p和Nb 4d电子占据;导带则主要由Nb 4d轨道构成;C掺杂NaNbO3后在禁带中形成了三条由C 2p轨道构成的杂质能级且费米能级通过杂质能级;纯NaNbO3仅在紫外光区有较强的光吸收;C掺杂NaNbO3的光吸收扩展了可见光区。

The band structures, density of states and absorption spectrum of pure and C doped NaNbO3 have been studied by the first principle methods based on density functional theory. The calculated results indicate that the valence band of pure NaNbO3 is dominated by O 2p and Nb 4d states while the conduction band is mainly composed ofNb 4d orbitals. In addition to the O 2p and Nb 4d states, three C 2p states are found in the forbidden band for C doped NaNbO3. Moreover, for the pure NaNbO3, the strong absorptions are only observed in UV region while the absorption in visible-light region can also be found for C doped NaNbO3.