Rhenium substitutional doping for enhanced photoresponse of n-SnSe2/p-Si heterojunction based tunable and high-performance visible-light photodetector

Abstract

The low photoresponse of solution-processed 2D/3D heterojunctions is still a challenging factor in terms of the efficient output of the device as a photodetector. Here, we have doped tin diselenide (SnSe2) with Rhenium (Re) transition metal by Direct Vapor Technique (DVT). The bulk doped SnSe2 then scale down to the nanoscale dimension by liquid-phase exfoliation (LPE) method. Synthesized nanocrystals exhibit the multilayered structure and nanometer dimensions with a good crystalline structure. The incorporation of Re is confirmed by EDAX, XRD, and Raman Spectroscopy. The Re incorporation in SnSe2 host lattice enhances the absorption in the visible region as compare to pristine SnSe2. The n-type Re doping decreases the turn-on voltage extracted from the Si-based heterojunction device measurements. The doped n-SnSe2/p-Si photodetector achieved the peak photoresponsivity (Rλ) and Detectivity (D*) of 7.90 A/W and 16.47 × 1012 respectively, at −2 V, which are ~2.8 and ~2.6 times higher than that of the pristine n-SnSe2/p-Si photodetector. This can be attributed to pronounce light-matter interaction and shifting of Fermi level towards to conduction band providing more charge carriers to participate in electrical conduction. Our work provides archetype for metal doping in multilayered semiconductor for high-performance optoelectronics devices.