Enhanced Electrical and Optoelectronic Characteristics of Few-Layer Type-II SnSe/MoS₂ van der Waals Heterojunctions

Abstract

van der Waals heterojunctions formed by stacking various two-dimensional (2D) materials have a series of attractive physical properties, thus offering an ideal platform for versatile electronic and optoelectronic applications. Here, we report few-layer SnSe/MoS van der Waals heterojunctions and study their electrical and optoelectronic characteristics. The new heterojunctions present excellent electrical transport characteristics with a distinct rectification effect and a high current on/off ratio (∼1 × 10). Such type-II heterostructures also generate a self-powered photocurrent with a fast response time (<10 ms) and exhibit high photoresponsivity of 100 A W, together with high external quantum efficiency of 23.3 × 10% under illumination by 532 nm light. Photoswitching characteristics of the heterojunctions can be modulated by bias voltage, light wavelength, and power density. The designed novel type-II van der Waals heterojunctions are formed from a combination of a transition-metal dichalcogenide and a group IV-VI layered 2D material, thereby expanding the library of ultrathin flexible 2D semiconducting devices.

Near-Direct Bandgap WSe2/ReS2 Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

“…Furthermore, a closer look at Figure 1c shows a type-II bandstructure necessary for efficient separation of the photogenerated electrons and holes 42,43 and can offer strong interlayer coupling via tunnelling of the majority carriers. 6,42 This is further reinforced by strong photoluminescence quenching ( Figure 3) and the region-wise photoresponse ( Figure 5d) indicates maximum photoresponse at the WSe2/ReS2 interface region. Figure 1d also which illustrates a schematic representation of the projected bandstructure shown in Figure 1c, where the conduction and valence band offsets (∆EC and ∆EV ) are 0.61 eV and 0.58 eV, respectively.…”

Ultrasensitive MoS2 photodetector by serial nano-bridge multi-heterojunction

“…Since the report of a single-layer MoS 2 photodetector 11 , recently, studies on MoS 2 -based photodetectors with various structures/functionalization such as mechanically exfoliated MoS 2 7,12 , gate functionalization 13–15 , high-κ (Al 2 O 3 and HfO 2 ) encapsulation 16,17 , phase transition (2H-1T) 18,19 , p-type (AuCl 3 ) 20 or n-type [PPh 3 and (3-aminopropyl) triethoxysilane (APTES)] 21,22 doping, perovskite heterostructure 10,23 , hybrid structure consisting of MoS 2 /PbS 24 , MoS 2 /TiO 2 /PbS 25 , MoS 2 /TiO 2 /HgTe 26 quantum dots and MoS 2 /Rhodamine 6 G (R6G) 27 , and van der Waals (vdW) heterojunction consisting of MoS 2 /black phosphorus (BP) 28 , MoS 2 /graphene 29 , MoS 2 /SnSe 30 , MoS 2 /GaTe 31 , and MoS 2 /GaSe 32 have been actively performed. The photoresponsivity and photoresponse of MoS 2 -based photodetectors have been greatly improved by these various studies.…”

A high performance self-driven photodetector based on a graphene/InSe/MoS2 vertical heterostructure

“…In addition, other vertical VDW heterostructures with p-n junctions such as GaTe/InSe, black phosphorus/MoS 2 and SnSe/MoS 2 have been reported. All of them show diode-like behavior and photovoltaic effect due to the type-II VDW heterojunctions [10][11][12][13] . The self-driven behavior in a photodetector is based on the photovoltaic effect and should in principle be seen in devices based on type-II VDW heterojunctions because of the built-in potential.…”