不同浓度Cu掺杂SnO2材料电学和力学性质的研究

为研究Cu掺入对SnO_2性能的影响,本文采用密度泛函理论和平面波赝势法,建立了未掺杂SnO_2和不同比例Cu掺杂的SnO_2晶胞模型,对Sn_(1-x)Cu_xO_2(x=0、0.083、0.125、0.167、0.25、0.5)超晶胞体系进行优化计算、能量计算和弹性模量计算,得到晶格常数、弹性模量、电荷分布、能带结构和态密度图.研究表明:掺杂能够使得材料的弹性模量大幅减小,对应的硬化函数值降低,易于材料加工;在电性质方面,掺杂后,材料均属于直接带隙半导体材料.当x0.25时,由于掺杂浓度过高使得晶格发生畸变,电性质与未掺杂情况类似;当x0.25时,随着掺杂浓度的降低,导带收缩加剧,局域性增强,禁带宽度变窄,使得电子从价带受激跃迁所需能量降低,故掺杂后材料表现出半金属性,导电性增强.

Study on electrical and mechanical properties of Cu doped SnO2 with different concentration

To investigate the influence of Cu doping on the properties of SnO2 , by using density functional theory and plane wave pseudopotential method, built were the crystal cells,which include SnO2 and SnO2 with different proportion of Cu. The energy and elastic modulus of Sn1-xCuxO2(x=0,0.083,0.125,0.167,0.25,0.5) supercell system were calculated and optimized to obtain the lattice constant, elastic modulus, charge distribution, band structure and density of states. The results show that the doping can greatly reduce the elastic modulus of the material, reduce the hardening function value, be easy for the material processing. For the electrical properties, the material belongs to the direct bandgap semiconductor material after doping. When x> 0.25, the lattice is distorted due to the high doping concentration, and the electrical properties are similar to the undoped state. When x<0.25, with the decrease of doping concentration, the conduction band shrinkage, the localized enhancement, band gap narrowing, reduce the energy requirement for electron stimulated transition. So the material after the doping shows semi-metallic with electrical conductivity enhancement.