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基于密度泛函理论第一性原理的方法计算了N掺杂ZnO纳米线的形成能、能带结构和态密度。研究了N掺杂浓度和N原子替换掺杂位置对ZnO纳米线结构的稳定性和能带结构的影响。计算结果表明,未掺杂的ZnO纳米线为直接带隙半导体,理论计算的带隙值为1.74 eV。当N掺杂的摩尔分数为2.08%(1个N原子掺杂)时,N替换ZnO纳米线第一层最外层位置处的O原子时,体系形成能最低,为4.398 eV,纳米线结构最为稳定;而当N掺杂的摩尔分数为4.16%(2个N原子掺杂)时,N替换ZnO纳米线第一层最外层和中心位置处的O原子时体系形成能最低,为8.508 eV,纳米线结构最为稳定。此外,两种N掺杂的ZnO纳米线分别在价带顶上方0.49 eV和0.63 eV处形成N杂质能级,1个N原子掺杂的纳米线结构比2个N原子掺杂的纳米线结构具有更浅的N杂质能级。因此,低N掺杂量更容易对ZnO纳米线结构进行p型掺杂,从而为实现p型N掺杂ZnO纳米线提供理论分析依据。
The formation energy, the band structure and the density of states of N-doped ZnO nanowires were calculated based on the first-principles of density functional theory. The effects of N doping concentration and substitution position of N atoms on the stability and band structure of ZnO nanowires were investigated. The calculated results show that the undoped ZnO nanowires are direct band gap semiconductors, and the theoretical calculated band gap is 1.74 eV. When the molar fraction of N doping is 2.08% (1 N atom doping), when N replaces the O atom at the outermost layer of the first layer of ZnO nanowire, the lowest formation energy is 4.398 eV. The nanowire structure Which is the most stable when N atom is 4.16% (2 N atoms). When N is replaced by O atoms in the outermost layer and the center of the first layer of ZnO nanowires, the formation energy is the lowest, which is 8.508 eV, the most stable structure of nanowires. In addition, the two N-doped ZnO nanowires form N impurity levels at 0.49 eV and 0.63 eV respectively above the top of the valence band, with one N-doped nanowire structure compared to two N-doped nanowire structures With a shallower N impurity level. Therefore, the low N doping makes it easier to p-type the ZnO nanowire structure, which provides a theoretical basis for the realization of p-type N-doped ZnO nanowires.