Atomic-layered material BiOSe has emerged as a novel two-dimensional (2D) semiconductor with the moderate band gap, high carrier mobility and excellent environmental stability, showing great potential for many applications such as the design of photodetectors. However, in 2D BiOSe various structural defects are inevitable and these structural defects will significantly affect the physical and chemical properties. Here, combining density functional theory with non-equilibrium Green’s function, we systematically investigated the structures, electronic and photoelectronic properties of the adsorption-, vacancy-, antisite- and exchange-typelinedefects in 2D BiOSe. The obtained results suggest that the adsorption-type line defects can enhance the thermodynamic stability of 2D BiOSe and that the vacancy- and exchange-type line defects weaken the thermodynamic stability. While the antisite-type line defects have complicated thermodynamic behaviors. The line defects usually give rise to significant influences on the hole effective masses of 2D BiOSe and, more interestingly, typical metallized phenomena have been observed for some line defects. Compared with the perfect 2D BiOSe, we also found that some line defects can increase the photocurrents in the infrared and ultraviolet regions noticeably. While in the visible region the line defects exhibit richphotoelectronic properties.

中文翻译：

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二维Bi2O2Se线缺陷的结构、电子和光电性质

原子层材料BioSe已成为一种新型二维（2D）半导体，具有适中的带隙、高载流子迁移率和优异的环境稳定性，在光电探测器设计等许多应用中显示出巨大的潜力。然而，在2D BioSe中，各种结构缺陷是不可避免的，这些结构缺陷将显着影响物理和化学性能。在这里，我们将密度泛函理论与非平衡格林函数相结合，系统地研究了二维BioSe中吸附型、空位型、反位型和交换型线缺陷的结构、电子和光电性质。结果表明，吸附型线缺陷可以增强2D BioSe的热力学稳定性，而空位型和交换型线缺陷则削弱热力学稳定性。而反位点型线缺陷则具有复杂的热力学行为。线缺陷通常会对2D BioSe的空穴有效质量产生显着影响，更有趣的是，在一些线缺陷中观察到了典型的金属化现象。与完美的2D BioSe相比，我们还发现一些线缺陷可以显着增加红外和紫外区域的光电流。而在可见光区域，线缺陷表现出丰富的光电特性。