Broadband and High-Performance Photodetector Fabricated Using Large Area and Transfer-Free 2D-2D PtS₂/MoS₂ Heterostructure

2D transitional metal dichalcogenide (TMDC) materials have shown great potential in the optoelectronics and electronics field owing to their unique and favorable properties. However, developing high-performance broadband photodetectors in bare TMDC material is impeded due to their limited absorption and poor charge-carrier separation. The recent advancement in van der Waals heterostructure fabrication has exhibited a new path to improve the device performance. In the present work, a facile approach is presented to fabricate a large area of PtS2/MoS2 heterostructure, which demonstrates a broad spectral detection range from 400 to 1200 nm with high responsivity (30.2 A W-1) and detectivity (1.12 x 10(13) Jones) even under near-infrared (NIR) 900 nm light illumination at moderate bias. Moreover, the PtS2/MoS2 photodetector exhibits a much enhanced responsivity (97 times) and detectivity (33 times) compared with bare MoS2. A rise/fall time of 11 ms/10 ms for the PtS2/MoS2 device represents its fast response speed. The X-ray photoelectron spectroscopy measurements reveal the type-I band alignment between the PtS2 and MoS2, which are further utilized to understand the charge carrier dynamics between the PtS2 and MoS2 interface. This work presents a simple strategy to synthesize scalable, high-performance broadband photodetectors for future optoelectronics applications.