GGA+U方法研究不同浓度镧(La)与氮(N)掺杂纤锌矿ZnO的光学性质

本文运用基于密度泛函理论的GGA+U方法,计算了纯ZnO体系,La、N单掺ZnO体系及Zn_(1-x)La_xO_(0.875)N_(0.125)(x=0.125,0.25,0.375)三个共掺体系的电子结构和光学性质.计算结果表明,共掺体系中随着La浓度的增加,掺杂后体系的禁带宽度变小,电子跃迁所需能量减小,晶格畸变程度增大,有利于阻碍光生空穴和电子对的复合,吸收光谱吸收带边红移程度越来明显,覆盖了整个可见光区域.这些特征非常有利地说明共掺体系随La浓度的增加,其光催化功能和电学性能也在提升.

GGA+U Method Study on Optical Properties of Different Concentrations of La (Z) and Nitrogen (N) Doped Wurtzite ZnO

In this paper, the GGA+U method based on density functional theory, is used to calculate the electronic structures and optical properties of pure ZnO, La doped, and N doped ZnO systems, and Zn1-nLanO0.875N0.125 (n=0.125, 0.25, 0.375). The calculation results show that with the increase of La concentration in the co-doped system, the forbidden band width of the doped system becomes smaller, the energy required for electronic transition decreases, the lattice distortion is large, which is beneficial to hinder the composite of photogenerated holes and electron pairs, and the absorbing edge of the absorption spectrum redshifts more obviously, the absorption spectrum covering the entire visible region. These characteristics are very advantageous to illustrate that the photocatalytic and electrical properties of the co-doped systems are improved with the increase of La concentration.