Abstract ZnS is one of the important optical materials for thermal imaging, infrared detecting and laser transmission. Herein, the point defects formation mechanism of hot-pressing ZnS and their influence on optical properties were systematically explored by density functional theory (DFT) to fully understand the experimental observation what the transmittance decreases and the black fogs form with the S vacancies increasing for the hot-pressing ZnS ceramics. Zn (VZn) and S (VS) point vacancies with various amounts of defect concentrations in the range from 0 to 50% were systematically studied to corresponding the experimental results. The result indicates that anion VS are energetically more favorable in regards to cation VZn based on their formation energies. This result explains why only VS were observed in the experiment. Electronic structures show that the band gaps vary from 3.858 eV to 1.569 eV, corresponding to the VS concentration from 0 to 25%. Consequently, the VS also lead to the reflectivity increase and the decrease of the optical transmittance. Continuation of increasing the VS concentrations to 50%, ZnS turns into metallic behavior without a distinctive band gap, so the light fails to pass and maybe cause black fogs formation.

中文翻译：

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了解热压过程引起的高浓度点缺陷 ZnS 的电子和光学特性：第一性原理计算

摘要 硫化锌是热成像、红外探测和激光传输的重要光学材料之一。在此，通过密度泛函理论（DFT）系统地探索了热压硫化锌的点缺陷形成机制及其对光学性能的影响，以充分理解实验观察结果，随着 S 空位的增加，透射率降低和形成黑雾。热压硫化锌陶瓷。系统地研究了具有 0 到 50% 范围内各种缺陷浓度的 Zn (VZn) 和 S (VS) 点空位以对应实验结果。结果表明，基于形成能，阴离子 VS 在能量上比阳离子 VZn 更有利。这个结果解释了为什么在实验中只观察到 VS。电子结构显示带隙从 3.858 eV 到 1.569 eV，对应于 0 到 25% 的 VS 浓度。因此，VS 也导致反射率增加和光透射率降低。继续将 VS 浓度增加到 50%，ZnS 变成没有明显带隙的金属行为，因此光无法通过并可能导致形成黑雾。