Fast and high-responsivity MoS2/MoSe2 heterostructure photodetectors enabled by van der Waals contact interfaces

Two-dimensional (2D) materials are ideal candidates for building optoelectronic devices, owing to their fascinating photoelectric properties. However, most photodetectors based on individual 2D materials face difficulties in achieving both high responsivity and fast response. In this paper, we have fabricated high-quality vertically stacked MoS2/MoSe2 van der Waals (vdW) heterostructures using dry transfer method. The strong built-in electric field at the interface of type II heterostructure effectively facilitates the separation of photogenerated carriers. The vdW contact between channel material and transferred metal electrode effectively avoids the introduction of defects. These methods effectively enhance the performance of hybrid devices. Under 532 nm laser illumination, this photodetector exhibits high responsivity (528.1 A/W) and fast photoresponse (rise time similar to 3.0 mu s/decay time similar to 31.3 mu s). Furthermore, we demonstrated single-pixel image sensing capabilities of the device at room temperature across various modulation frequencies. Importantly, imaging at a frequency as high as 15 000 Hz was attained, indicating its great potential for next-generation, high-performance single-pixel image sensing applications.