In-Plane Mosaic Potential Growth of Large-Area 2D Layered Semiconductors MoS-MoSe Lateral Heterostructures and Photodetector Application.

Considering the unique layered structure and novel optoelectronic properties of individual MoS and MoSe, as well as the quantum coherence or donor-acceptor coupling effects between these two components, rational design and artificial growth of in-plane mosaic MoS/MoSe lateral heterojunctions film on conventional amorphous SiO/Si substrate are in high demand. In this article, large-area, uniform, high-quality mosaic MoS/MoSe lateral heterojunctions film was successfully grown on SiO/Si substrate for the first time by chemical vapor deposition (CVD) technique. MoSe film was grown along MoS triangle edges and occupied the blanks of the substrate, finally leading to the formation of mosaic MoS/MoSe lateral heterojunctions film. The composition and microstructure of mosaic MoS/MoSe lateral heterojunctions film were characterized by various analytic techniques. Photodetectors based on mosaic MoS/MoSe lateral heterojunctions film, triangular MoS monolayer, and multilayer MoSe film are systematically investigated. The mosaic MoS/MoSe lateral heterojunctions film photodetector exhibited optimal photoresponse performance, giving rise to responsivity, detectivity, and external quantum efficiency (EQE) up to 1.3 A W, 2.6 × 10 Jones, and 263.1%, respectively, under the bias voltage of 5 V with 0.29 mW cm (610 nm), possibly due to the matched band alignment of MoS and MoSe and strong donor-acceptor delocalization effect between them. Taking into account the similar edge conditions of transition metal dichalcogenides (TMDCs), such a facile and reliable approach might open up a unique route for preparing other 2D mosaic lateral heterojunctions films in a manipulative manner. Furthermore, the mosaic lateral heterojunctions film like MoS/MoSe in the present work will be a promising candidate for optoelectronic fields.