High-Performance Broadband Image Sensing Photodetector Based on MnTe/WS 2 van der Waals Epitaxial Heterostructures.

Two-dimensional transition metal dichalcogenide (TMDC) heterostructure is receiving considerable attention due to its novel electronic, optoelectronic, and spintronic devices with design-oriented and functional features. However, direct design and synthesis of high-quality TMDC/MnTe heterostructures remain difficult, which severely impede further investigations of semiconductor/magnetic semiconductor devices. Herein, the synthesis of high-quality vertically stacked WS 2 /MnTe heterostructures is realized via a two-step chemical vapor deposition method. Raman, photoluminescence, and scanning transmission electron microscopy characterizations reveal the high-quality and atomically sharp interfaces of the WS 2 /MnTe heterostructure. WS 2 /MnTe-based van der Waals field effect transistors demonstrate high rectification behavior with rectification ratio up to 10 6 , as well as a typical p-n electrical transport characteristic. Notably, the fabricated WS 2 /MnTe photodetector exhibits sensitive and broadband photoresponse ranging from UV to NIR with a maximum responsivity of 1.2 × 10 3 A/W, a high external quantum efficiency of 2.7 × 10 5 %, and fast photoresponse time of ∼50 ms. Moreover, WS 2 /MnTe heterostructure photodetectors possess a broadband image sensing capability at room temperature, suggesting potential applications in next-generation high-performance and broadband image sensing photodetectors.