Graphene/SnS₂ van der Waals Photodetector with High Photoresponsivity and High Photodetectivity for Broadband 365–2240 nm Detection

Abstract

The fabrication of graphene/SnS 2 van der Waals photodetectors and their photoelectrical properties are systematically investigated. It was found that a dry transferred graphene/SnS 2 van der Waals heterostructure had a broadband sensing range from ultraviolet (365 nm) to near-infrared (2.24 μm) and respective improved responsivities and photodetectivities of 7.7 × 10 3 A/W and 8.9 × 10 13 jones at 470 nm and 2 A/W and 1.8 × 10 10 jones at 1064 nm. Moreover, positive and negative photoconductance effects were observed when the photodetectors were illuminated by photon sources with energies greater and smaller than the bandgap of SnS 2 , respectively. The photoresponsivity (R) versus incident power density (P) follows the empirical law R ∝ P in β , with β > −1 for positive photoconductance effects and β < −1 for negative photoconductance effects. On the basis of the Fowler−Nordheim tunneling model and a Poisson and drift-diffusion simulation, we show quantitatively that the barrier height and barrier width of the heterostructure photodetector could be controlled by a laser and an external electrical field through a photogating effect generated by carriers trapped at the interface, which could be used to tune the separation and transport of photogenerated carriers. Our results may be useful for the design of high performance van der Waals heterojunction photodetectors.

Light-Tunable Polarity and Erasable Physisorption-Induced Memory Effect in Vertically Stacked InSe/SnS2 Self-Powered Photodetector

“…It was found that the thicknesses of the SnS 2 and InSe were about 31 and 30 nm, respectively (Figure S1). Therefore, in this work, the band gaps of the exfoliated InSe and SnS 2 flakes were set to be 1.3 and 2.2 eV, − respectively. Kelvin probe force microscopy (KPFM) was employed to determine the surface potential of SnS 2 and InSe before and after assembly of the SIH (Figure S2).…”

Laser Irradiation Effect on the p-GaSe/n-HfS2 PN-Heterojunction for High-Performance Phototransistors

“…Moreover, the ON/OFF ratio and short-circuit current linearly decrease by increasing the laser power density (see Figure e). Figure f reports the compared photoresponsivity with other reported device results in the literature. ,,,,− The calculated compelling figures of merit of p-GaSe/n-HfS 2 vdW heterostructure are further summarized in Table . The detailed calculated parameters of the p-GaSe/n-HfS 2 vdW heterostructure before and after 690 mW cm –2 laser irradiation are shown in Table .…”

“…The reduced SS value directs better channel control and faster transition between off and on currents. The photovoltaic parameters reveal that the device has improved performance compared to other 2D heterostructures. ,,,− …”

Highly-Responsive Broadband Photodetector Based on Graphene-PTAA-SnS2 Hybrid

“…Li et al stacked the hexagonal SnS 2 with orthorhombic SnS flake through a one-step CVD method for a vertical SnS 2 /SnS heterostructure, and the obtained photodetectors demonstrated a high optoelectronic performance with a responsivity of 27.7 A/W [ 36 ]. Zhao et al mechanically exfoliated the graphene and SnS 2 to form a graphene/SnS 2 van der Waals heterostructure in photodetectors, and they achieved a broadband photoresponse with a highest responsivity up to 7.7 × 10 3 A/W at 365 nm [ 37 ]. However, the complexity, high cost and limited controllability for the fabrication of both 2D material layers in heterostructures with either CVD or mechanical-exfoliation hinder the applications of SnS 2 in broadband photodetectors.…”