氮掺杂对4H-SiC电子结构的影响

The impact of doping nitrogen on the electronic structure of 4H-SiC

采用广义梯度近似的密度泛函理论方法计算了4H-SiC的本征态的电子结构以及4H-SiC材料N掺杂后的电子结构,计算结果表明:与本征态相比,N掺杂后的4H-SiC的导带与价带均向低能端移动,导带移动幅度大于价带,使得掺杂后的禁带宽度小于本征态的禁带宽度:导带底进入N的2s态和2p态,但它们所占比重小,掺杂浓度变化对导带底影响较小;价带顶进入N的2p态,随掺杂浓度增加,其向低能端移动较多,使得禁带宽度增大。

The electronic structure of the 4H - SiC eigenstates and that of n - type doped 4H - SiC are calculated by the generalized gradient approximation, results show that：compared with the eigenstates, N doped The 4H- SiC conduction＇s band and valence band move to the low energy end, but the moving extent of conduction band is greater than that of valence band. So the band gap of doped 4H - SiC is smaller than that of eigenstates; conduction band moves into the 2s state and 2p states of N, but they share a small, daping concentration has little impact on the bottom of conduction band; the top of valence band moves into the 2p states of N, with the doping concentration increasing, the top of valence band move to low energy end and band gap Increases.