摘要:
目前,在V高掺杂ZnO中,当V掺杂量摩尔数为0.03125-0.04167的范围内,掺杂量越增加,电阻率越增加或越减小的两种实验结果均有文献报道.为解决这个矛盾,本文采用密度泛函理论的第一性原理平面波超软赝势方法,构建未掺杂ZnO, V高掺杂的Zn1-xVxO (x=0.03125,0.04167)两种超胞模型,首先,对所有体系进行几何结构优化,在此基础上,采用GGA+U的方法,计算所有体系的能带结构分布、态密度分布、吸收光谱分布.结果表明,当掺杂量摩尔数为0.03125-0.04167的范围内, V掺杂量越增加,掺杂体系体积越增加,总能量越下降,形成能越减小,掺杂体系越稳定,相对电子浓度越减小,迁移率越减小,电导率越减小,最小光学带隙越增加,吸收光谱蓝移越显著.计算结果与实验结果相一致.
Abstract:
Nowadays, in the reports of V-heavy-doped ZnO, when the doping moles of V in the range of 0.03125 to 0.04167, there is a current controversy between the two experimental results, i.e. the conductivity may be increased or decreased as the doping content increases. To solve this contradiction, the undoped and the two different concentrations of heavy-doped V atoms in Zn1-xVxO(x=0.03125, 0.04167) compounds have been set up based on the first-principles plane wave ultra-soft pseudo potential method of density functional theory in this paper, then all three compunds are geometrically optimized, and on this basis the GGA+U method is adopted to calculate the band structures, density of states, and the absorption spectrum. Results reveal that when the doping mole of V is in the range of 0.03125 to 0.04167, the volume doped system of the is increased as the total energy decreases; as the doping mole of V increases, the formation energy is reduced, the doping system is more stable, and the relative electronic concentration decreases, the migration rate and the conductivity are reduced;as the optical band gap is enlarged, the absorption spectrum blue shift is more significant. There are in agreement with the experimental results.
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