Abstract

Consequences of incorporation of magnesium atom(s) on structural and optoelectronic properties of wurtzite cadmium sulphide have been investigated from first-principle calculations. Like direct (Γ–Γ) band-gap end binary wurtzite cadmium and magnesium sulphide semiconductors, such incorporation also results in stable direct (Γ–Γ) band-gap wurtzite Mg_xCd_1−xS semiconductor ternary alloys with band-gaps residing in the UV spectral region. Lattice constants (a₀, c₀) of specimens within the w-Mg_xCd_1−xS system nonlinearly reduce, while fundamental band-gap (E_g) enhances with increasing Mg content. Optical characteristics of optically anisotropic wurtzite crystals are studied mainly with ordinary and extraordinary components of real and imaginary parts of the complex dielectric function and some other dependent optical parameters. Electronic transitions from valence S-3p to Mg-4s, Mg-4p, Cd-5s and Cd-4p states of conduction band jointly result in optical features of the ternary alloys. Each uniaxial wurtzite crystal shows birefringence. Optical energy gap (E_opt) of each ternary alloy, higher than the corresponding E_g, lies in the UV region. Calculated components of static optical constants for ternary alloys become lower, but critical point energies become higher for larger band-gap specimen and vice versa. High optical absorption of direct band-gap ternary alloys in the UV region leads them as a compatible semiconductor for fabricating faster UV optoelectronic devices with high efficiency.

中文翻译：

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镁掺入对纤锌矿硫化镉结构和光电性能的影响：基于第一原理的紫外光电应用理论研究

摘要

通过第一性原理计算研究了镁原子的掺入对纤锌矿硫化镉的结构和光电性质的影响。与直接（Г–Г）带隙端二元纤锌矿镉和硫化镁半导体一样，这种掺入也导致稳定的直接（Г–Н）带隙纤锌矿Mg x _Cd 1− _{x S}半导体三元合金，具有带隙驻留在紫外光谱区。w -Mg _x Cd _{1− x} S 系统中样品的晶格常数 ( a ₀ , c ₀ )非线性减小，而基本带隙 ( E _g ) 随着 Mg 含量的增加而增强。主要利用复介电函数实部和虚部的寻常分量和非常分量以及其他一些相关光学参数来研究光学各向异性纤锌矿晶体的光学特性。电子从价态S-3p到导带Mg-4s、Mg-4p、Cd-5s和Cd-4p态的跃迁共同导致了三元合金的光学特征。每个单轴纤锌矿晶体都显示出双折射。每种三元合金的光学能隙（E _opt）均高于相应的E _g，位于紫外区域。三元合金的静态光学常数的计算分量变得更低，但带隙较大的样品的临界点能量变得更高，反之亦然。直接带隙三元合金在紫外区域的高光吸收使其成为一种兼容的半导体，可用于制造更快、更高效的紫外光电器件。