Sui Fengrui, Jin Min, Zhang Yuanyuan, Hong Jin, Cheng Yan, Qi Ruijuan, Yue Fangyu, Huang Rong
Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, People's Republic of China.
College of Materials, Shanghai Dianji University, Shanghai 201306, People's Republic of China.
J Phys Condens Matter. 2022 Mar 31;34(22). doi: 10.1088/1361-648X/ac5e07.
As a narrow-gap semiconductor, III-VI two-dimensional (2D) van der Waals layered indium selenide (InSe) has attracted a lot of attention due to excellent physical properties. For potential optoelectronic applications, the tunability of the optical property is challenging, e.g., the modulation of optical bandgap commonly by element doping. However, the deep understanding of the influence of element doping on the microstructure and the optical properties lacks of systematic investigation. In this work, by using aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, we investigate the influence of Bi doping on controlling of the microstructure and optical properties of InSe single crystal in detail. The results show that Bi doping can introduce additional stacking faults in InSe single crystal, and more importantly, the atomic spacing and lattice constant of Bi-doped InSe are changed a lot as compared to that of the undoped one. Further optical characterizations including photoluminescence and transmission spectra reveal that Bi-doping can broaden the transmission wavelength range of InSe and make its optical bandgap blue-shift, which can also be physically interpreted from the doping-induced structure change. Our work expands new ideas for the optical property modulation of 2D thin-layer materials and brings new possibilities for the development of thin-layer InSe optical devices.
作为一种窄带隙半导体，III-VI族二维（2D）范德华层状硒化铟（InSe）因其优异的物理性质而备受关注。对于潜在的光电子应用而言，光学性质的可调控性具有挑战性，例如通常通过元素掺杂来调制光学带隙。然而，目前对于元素掺杂对微观结构和光学性质的影响缺乏系统的深入研究。在这项工作中，我们使用像差校正的高角度环形暗场扫描透射电子显微镜，详细研究了Bi掺杂对InSe单晶微观结构和光学性质的影响。结果表明，Bi掺杂会在InSe单晶中引入额外的堆垛层错，更重要的是，与未掺杂的InSe相比，Bi掺杂的InSe的原子间距和晶格常数发生了很大变化。包括光致发光和透射光谱在内的进一步光学表征表明，Bi掺杂可以拓宽InSe的透射波长范围并使其光学带隙蓝移，这也可以从掺杂引起的结构变化进行物理解释。我们的工作为二维薄层材料的光学性质调制拓展了新思路，并为薄层InSe光学器件的发展带来了新的可能性。
