Localized electric-field-enhanced low-light detection by a 2D SnS visible-light photodetector*

Abstract

Due to their excellent carrier mobility, high absorption coefficient and narrow bandgap, most 2D IVA metal chalcogenide semiconductors (GIVMCs, metal = Ge, Sn, Pb; chalcogen = S, Se) are regarded as promising candidates for realizing high-performance photodetectors. We synthesized high-quality two-dimensional (2D) tin sulfide (SnS) nanosheets using the physical vapor deposition (PVD) method and fabricated a 2D SnS visible-light photodetector. The photodetector exhibits a high photoresponsivity of 161 A⋅W−1 and possesses an external quantum efficiency of 4.45 × 104%, as well as a detectivity of 1.15 × 109 Jones under 450 nm blue light illumination. Moreover, under poor illumination at optical densities down to 2 mW⋅cm−2, the responsivity of the device is higher than that at stronger optical densities. We suggest that a photogating effect in the 2D SnS photodetector is mainly responsible for its low-light responsivity. Defects and impurities in 2D SnS can trap carriers and form localized electric fields, which can delay the recombination process of electron-hole pairs, prolong carrier lifetimes, and thus improve the low-light responsivity. This work provides design strategies for detecting low levels of light using photodetectors made of 2D materials.

High-performance broadband SnS photodetector based on photoconductive-bolometric coupling effect

“…Table 1 provides a summary of the performance characteristics of previously reported PDs of the same type [21,[33][34][35][36][37]. Benefiting from the photoconductive-bolometric coupling effect, the SnS PD in this work exhibits a broadband response far exceeding that of other devices, especially showing high responsivity and detectivity.…”

“…Presently, most widely used methods to grow 2D films mainly include, hydrothermal method [20], physical vapor deposition (PVD) [21], chemical vapor deposition (CVD) [22] and solution reaction technique [23]. Among these methods, vdW growth of the related 2D film on the substrate was realized.…”

Edge assisted epitaxy of CsPbBr3 nanoplates on Bi2O2Se nanosheets for enhanced photoresponse

“…Two-dimensional (2D) semiconductor materials have attracted extensive research interest for both the fundamental physics researches and the practical applications in electronic and optoelectronic devices, due to their unique optical and electrical properties. [1][2][3][4][5][6][7][8] Recently, Bi 2 O 2 Se, an emerging 2D material, has been proved to possess typical narrow bandgap, high carrier mobility and superior air stability, which makes it a promising candidate for high-performance devices, such as field effect transistors (FETs), broadband photodetectors (PDs) and ultrafast photodetection. [9][10][11][12][13][14][15][16][17][18][19][20] Because the heterointerfaces directly determine the operation of modern electronic devices, [21][22][23][24] the fabrication of Bi 2 O 2 Se-based heterostructures is crucially important for practical applications of the related devices.…”