Department of Chemistry , Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016 , India.
Department of Physics , Indian Institute of Technology Kharagpur , Kharagpur 721302 , West Bengal , India.
ACS Appl Mater Interfaces. 2019 Jan 30;11(4):4074-4083. doi: 10.1021/acsami.8b16205. Epub 2019 Jan 18.
Heterostructures based on atomically thin two-dimensional layered transition metal dichalcogenides are highly promising for optoelectronic device applications owing to their tunable optical and electronic properties. However, the synthesis of heterostructures with desired materials having proper interfacial contacts has been a challenging task. Here, we develop a colloidal synthetic route for the design of MoSe-CuS nanoheterostructures, where the CuS islands grow vertically on top of the defect sites present on the MoSe surface, thereby forming a vertical p-n junction having plasmonic characteristics. These MoSe-CuS nanoheterostructures are used to fabricate photodetectors with superior photoresponse characteristics. The fabricated device exhibits a broad-band spectral photoresponse over the visible to near-infrared range with a peak responsivity of 410 mA W at -2.0 V and over 3000-fold photo-to-dark current ratio. The superior device performance of MoSe-CuS over only MoSe devices is due to the combined effect of the formation of the p-n junction, pronounced light-matter interactions, and passivation of surface defects. This study would pave the way for designing a new class of nanoheterostructured materials for their potential applications in next-generation photonic devices.
基于原子层厚二维过渡金属二硫属化物的异质结构由于其可调谐的光学和电子特性，在光电器件应用中极具前景。然而，具有适当界面接触的所需材料的异质结构的合成一直是一项具有挑战性的任务。在这里，我们开发了一种胶体合成方法来设计 MoSe-CuS 纳米异质结构，其中 CuS 岛垂直生长在 MoSe 表面的缺陷位置上，从而形成具有等离子体特性的垂直 p-n 结。这些 MoSe-CuS 纳米异质结构被用于制造具有优越光电响应特性的光探测器。所制造的器件在可见光到近红外范围内表现出宽带光谱光电响应，在 -2.0 V 时的峰值响应率为 410 mA W，光电流与暗电流的比值超过 3000 倍。MoSe-CuS 器件的性能优于仅 MoSe 器件，这是由于 p-n 结的形成、显著的光物质相互作用以及表面缺陷的钝化的综合作用。这项研究为设计一类新型纳米异质结构材料铺平了道路，有望将其应用于下一代光子器件。
