CAJ | 학술논문

采用基于密度泛函理论的第一性原理平面波超软赝势计算方法,研究了In、Sc p型掺杂对SrTiO_3母体化合物稳定性、电子结构和光学性质的影响.计算结果表明:掺杂后,SrIn_(0.125)Ti_(0.875)O_3和SrSc_(0.125)Ti_(0.875)O_3的稳定性降低,体系显示p型简并半导体特征,掺杂仅引起杂质原子近邻区域的几何结构发生变化.同时,SrIn_(0.125)Ti_(0.875)O_3和SrSc_(0.125)Ti_(0.875)O_3体系的光学带隙分别展寬0.35、0.30 eV,光学吸收边发生蓝移,在1.25.2.00 eV的能量区间出现新的吸收峰,该吸收峰与体系Drude型自由载流子的激发相关.此外,SrIn_(0.125)Ti_(0.875)O_3和SrSc_(0.125)Ti_(0.875)O_3体系的可见光透过率有了明显的提高,在350-625 nm波长范围透过率高于85%.掺杂原子在费米能级处低的电子态密度限制了跃迁概率和光吸收.大的禁带宽度、小的跃迁概率和弱的光吸收是SrIn_(0.125)Ti_(0.875)O_3和SrSc_(0.125)Ti_(0.875)O_3体系具有较高光学透明度的原因.
채용기우밀도범함이론적제일성원리평면파초연안세계산방법,연구료In、Sc p형참잡대SrTiO_3모체화합물은정성、전자결구화광학성질적영향.계산결과표명:참잡후,SrIn_(0.125)Ti_(0.875)O_3화SrSc_(0.125)Ti_(0.875)O_3적은정성강저,체계현시p형간병반도체특정,참잡부인기잡질원자근린구역적궤하결구발생변화.동시,SrIn_(0.125)Ti_(0.875)O_3화SrSc_(0.125)Ti_(0.875)O_3체계적광학대극분별전관0.35、0.30 eV,광학흡수변발생람이,재1.25.2.00 eV적능량구간출현신적흡수봉,해흡수봉여체계Drude형자유재류자적격발상관.차외,SrIn_(0.125)Ti_(0.875)O_3화SrSc_(0.125)Ti_(0.875)O_3체계적가견광투과솔유료명현적제고,재350-625 nm파장범위투과솔고우85%.참잡원자재비미능급처저적전자태밀도한제료약천개솔화광흡수.대적금대관도、소적약천개솔화약적광흡수시SrIn_(0.125)Ti_(0.875)O_3화SrSc_(0.125)Ti_(0.875)O_3체계구유교고광학투명도적원인.
The effect of In and Sc p-type doping on the structural stability, electronic structure, and optical properties of SrTiO_3 was investigated by first-principles calculations of plane wave ultra-soft pseudo-potential based on density functional theory (DFT). The calculated results revealed that the structural stability of SrTiPO_3 was weakened after In and Sc doping and that the partial substitution of In for Ti (or Sc for Ti) merely resulted in local structural changes around the dopant sites. The doped SrIn_(0.125)Ti_(0.875)O_3 and SrSc_(0.125)Ti_(0.875)O_3 systems are p-type degenerate semiconductors. The optical bandgap was broadened by about 0.35 eV for SrIn_(0.125)Ti_(0.875)O_3 and 0.30 eV for SrSc_(0.125)Ti_(0.875)O_3. In addition, a noticeable blue-shift of the absorption spectral edge was observed in the two p-type doping systems and a new absorption appeared at around 1.25 to 2.00 eV because of the Drude-type behavior of the free-carrier excitation. The optical transmittance of SrIn_(0.125)Ti_(0.875)O_3 and SrSc_(0.125)Ti_(0.875)O_3 improved significantly after doping and the transmittances were higher than 85% from 350 to 625 nm. The wide bandgap, small transition probability, and weak absorption because of the low partial density of states of impurities in the Fermi level result in SrIn_(0.125)Ti_(0.875)O_3 and SrSc_(0.125)Ti_(0.875)O_3 being optically transparent.