Visible-to-near-infrared photodetectors based on SnS/SnSe2 and SnSe/SnSe2 p−n heterostructures with a fast response speed and high normalized detectivity

Abstract The emergent two-dimensional (2D) material, tin diselenide (SnSe 2 ), has garnered significant consideration for its potential in image capturing systems, optical communication, and optoelectronic memory. Nevertheless, SnSe 2 -based photodetection faces obstacles, including slow response speed and low normalized detectivity. In this work, photodetectors based on SnS/SnSe 2 and SnSe/SnSe 2 p−n heterostructures have been implemented through a polydimethylsiloxane (PDMS)−assisted transfer method. These photodetectors demonstrate broad-spectrum photoresponse within the 405 to 850 nm wavelength range. The photodetector based on the SnS/SnSe 2 heterostructure exhibits a significant responsivity of 4.99 × 10 3 A∙W −1 , normalized detectivity of 5.80 × 10 12 cm∙Hz 1/2 ∙W −1 , and fast response time of 3.13 ms, respectively, owing to the built-in electric field. Meanwhile, the highest values of responsivity, normalized detectivity, and response time for the photodetector based on the SnSe/SnSe 2 heterostructure are 5.91 × 10 3 A∙W −1 , 7.03 × 10 12 cm∙Hz 1/2 ∙W −1 , and 4.74 ms, respectively. And their photodetection performances transcend those of photodetectors based on individual SnSe 2 , SnS, SnSe, and other commonly used 2D materials. Our work has demonstrated an effective strategy to improve the performance of SnSe 2 -based photodetectors and paves the way for their future commercialization.