Layered indium selenide (InSe), a new two-dimensional (2D) material with a hexagonal structure and semiconducting characteristics, is gaining increasing attention owing to its intriguing electronic properties. Here, by using first-principles calculations, we reveal that perfect InSe possesses high chemical stability against oxidation, superior to MoS₂. However, the presence of intrinsic Se vacancy (V_Se) and light illumination can markedly affect its surface activity. In particular, the excess electrons associated with the exposed In atoms at the V_Se site under illumination are able to remarkably reduce the dissociation barrier of O₂ to ∼0.2 eV. Moreover, under ambient conditions, the splitting of O₂ enables the formation of substitutional (apical) oxygen atomic species, which further cause the trapping and subsequent rapid splitting of H₂O molecules and ultimately the formation of hydroxyl groups. Our findings uncover the causes and underlying mechanisms of InSe surface degradation via defect-photo-promoted oxidations. Such results will be beneficial in developing strategies for the storage of the InSe material and its applications for surface passivation with boron nitride, graphene or In-based oxide layers.

中文翻译：

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InSe系的缺陷和基于光诱导的氧化和降解的原子尺度的机制†

层状硒化铟（InSe）是一种具有六边形结构和半导体特性的新型二维（2D）材料，由于其令人着迷的电子性能而受到越来越多的关注。在这里，通过使用第一性原理计算，我们发现，完美的InSe具有较高的抗氧化化学稳定性，优于MoS ₂。但是，固有硒空位（V _Se）和光照的存在会明显影响其表面活性。特别是，在光照下与V _Se位点处暴露的In原子相关的过量电子能够将O ₂的解离势垒显着降低至〜0.2 eV。而且，在环境条件下，O ₂分解能够形成取代的（顶端）氧原子物种，这进一步引起H ₂ O分子的捕集和随后的快速分裂，最终导致羟基的形成。我们的发现揭示了通过缺陷光促进的氧化作用导致InSe表面降解的原因和潜在机理。这样的结果将有利于开发用于存储InSe材料的策略及其在氮化硼，石墨烯或In基氧化物层表面钝化中的应用。