Abstract The formation energy and electronic properties of intrinsic defects in Ag2S are studied using first-principle calculations. Three possible intrinsic defect configurations are considered, including VAg_I, VAg_II and VS. The calculation results show that VAg defects are more energetic favorable than VS defects. It is found that electrical neutral VAg_I is energetically favorable over the negative charged VAg_I below EF = 0.335eV. We find electronic conductivity could be enhanced by introducing intrinsic VAg defects into crystalline Ag2S. Our electronic band structures show that the curvatures of conduction band minimum of Ag2S are much flatter than the curvatures of valence band maximum, suggesting that the effect masses of holes are much lighter than those of electrons. Compared to pristine Ag2S, the effective masses of holes get larger by introducing vacancy into crystal. Fermi level is passing through the valence band, suggesting Ag2S with VAg defect would be a better conductivity. Non-vanishing N(EF) as well as light effect masses of holes make Ag2S suitable for construction of highly conductive p-type materials.

中文翻译：

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本征空位缺陷对单斜晶Ag2S电子性质的影响

摘要 利用第一性原理计算研究了 Ag2S 中固有缺陷的形成能和电子特性。考虑了三种可能的固有缺陷配置，包括 VAg_I、VAg_II 和 VS。计算结果表明，VAg缺陷比VS缺陷更有利。发现在 EF = 0.335eV 以下，电中性 VAg_I 在能量上优于带负电的 VAg_I。我们发现可以通过将本征 VAg 缺陷引入晶体 Ag2S 来提高电子电导率。我们的电子能带结构表明，Ag2S 的导带最小值的曲率比价带最大值的曲率要平坦得多，这表明空穴的效应质量比电子的效应质量要轻得多。与原始的 Ag2S 相比，通过在晶体中引入空位，空穴的有效质量变大。费米能级通过价带，表明具有 VAg 缺陷的 Ag2S 将具有更好的导电性。不消失的 N(EF) 以及光效应质量的孔使 Ag2S 适合构建高导电 p 型材料。