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采用基于密度泛函理论的第一性原理计算了锐钛矿相和金红石相TiO_2:Nb的晶体结构、电子结构和光学性质.结果表明,在相等的摩尔掺杂浓度下(6.25%),锐钛矿相TiO_2:Nb的导带底电子有效质量小于金红石相TiO_2:Nb,且前者室温载流子浓度是后者的两倍左右,即具有更大的施主杂质电离率,从而解释了锐钛矿相TiO_2:Nb比金红石相TiO_2:Nb具有更优异电学性能的实验现象.光学计算也表明锐钛矿相在可见光区有更大的透过率,从而在理论上解释了锐铁矿相TiO_2:Nb比金红石相’riO_2:Nb更适于做透明导电材料的原因.计算结果与实验数据能较好符合.
The crystal structure, electronic structure and optical properties of anatase phase and rutile phase TiO_2: Nb were calculated by first principles based on density functional theory.The results show that at the same molar doping concentration (6.25%), sharp The effective electron mass in the conduction band of TiO_2: Nb is less than that of the rutile TiO_2: Nb, and the carrier concentration at room temperature is about twice that of the latter, which means larger donor impurity ionization rate, which explains the anatase Compared with the rutile phase TiO_2: Nb, the phase of TiO_2: Nb in the mineralogical phase has more excellent electrical properties.Optical calculations also show that the anatase phase has greater transmittance in the visible region, which theoretically explains the anatase phase of TiO_2 : Nb is more suitable than the rutile phase riO_2: Nb for transparent conductive materials. The calculated results are in good agreement with the experimental data.