Strain-controlled synthesis of ultrathin hexagonal GaTe/MoS₂ heterostructure for sensitive photodetection

Ultrathin hexagonal GaTe, with relatively high charge density, holds great potential in the field of optoelectronic devices. However, the thermodynamical stability limits it fabrications as well as applications. Here, by introducing two-dimensional MoS₂ as the substrate, we successfully realized the phase-controlled synthesis of ultrathin h-GaTe, leading to high-quality h-GaTe/MoS₂ heterostructures. Theoretical calculation studies reveal that GaTe with hexagonal phase is more thermodynamically stable on MoS₂ templates, which can be attributed to the strain stretching and the formation energy reduction. Based on the achieved p-n heterostructures, optoelectronic devices are designed and probed, where remarkable photoresponsivity (32.5 A/W) and fast photoresponse speed (<50 μs) are obtained, indicating well-behaved photo-sensing behaviors. The study here could offer a good reference for the controlled growth of the relevant materials, and the achieved heterostructure will find promising applications in future integrated electronic and optoelectronic devices and systems.