In-situ fabrication of PtSe2/MoS2 van der Waals heterojunction for self-powered and broadband photodetector.

In this study, we have achieved the successful fabrication of PtSe 2 /MoS 2 heterojunction through a novel hybrid approach. Platinum (Pt) sputtering-selenization two-step growth method is adopted enabling the direct growth of PtSe 2 thin films on MoS 2 nanosheet. With the utilization of the photovoltaic effect (PVE) [9], the device demonstrates remarkable self-drive capabilities while exhibiting a wide spectral response spanning from 405 nm to 1550 nm. [Display omitted] • Platinum (Pt) sputtering-selenization two-step growth method is adopted enabling the direct growth of PtSe 2 thin films on MoS 2 nanosheet. • The in-situ Fabrication of PtSe 2 /MoS 2 heterojunction photodetector has a high responsivity of 5.42 A/W at 1 V bias voltage. • Without any external bias, this photodetector has a broadband optical response in the 405 to 1550 nm wavelength range. Two-dimensional transition metal dichalcogenides (2DTMDs) and their van der Waals heterojunctions (vdWHs) have garnered significant attention working as the channel material of optoelectronics. The development of new heterojunction growth schemes may also provide better performance for optoelectronic devices. In this paper, PtSe 2 thin films with controllable size and thickness are directly grown on MoS 2 nanosheet by sputtering-selenization two-step growth method. The photodetector with PtSe 2 /MoS 2 heterojunction exhibits a type-I band alignment and leads to an impressive broadband spectral photoresponse (405 to 1550 nm). It can achieve responsivity as high as 5.42 A/W, a detectivity of 2.52 × 1010 Jones, and a fast response rate (92/112 μs for rise/fall time respectively). In addition, the device has excellent stability in the air atmosphere and keeps its photoresponse after even six months. The in-situ growth method provides a new scheme to construct heterojunctions of 2DTMDs and develop energy-efficient photodetectors with enhanced performance. It also supplements the practical production and application of large-scale broadband detectors. [ABSTRACT FROM AUTHOR]