Hydrothermally Derived Layered 2D SnS Nanosheets for Near Infra-Red (NIR) Photodetectors

We report a facile and low-cost deposition of Tin sulfide (SnS) nanosheets and its performance for Near Infra-red (NIR) Photodetection under the UV to NIR illumination. Orthorhombic phase of SnS has been observed in the phase identification analysis. The optical absorption edge was observed at 1030 nm, and the band gap was found to be 1.2 eV. Nanosheets morphology along with flakes identified from the scanning electron micrograph analysis. Photoresponse measurement was studied under dark and illumination with a constant bias voltage of 1.5 V and the enhanced photocurrent is observed. The higher spectral responsivity of 0.19 A/W at 1030 nm has been observed in spectral response curve recorded from 300 nm to 1100 nm. The cyclic photoresponse of the SnS photodetectors shows good cyclability with illumination turn on and off alternatively with the time interval of 20 s. The response time (
$\text{T}_{\mathrm {r}}$
) and recovery time (
$\text{T}_{\tau }$
) were found to be 2 s and 4 s, respectively. The detectivity
$D_{t}$
of the SnS nanosheets photodetector to be
$9.213\times 10 ^{11}$

Jones
. The wavelength-dependent photodetection shows the maximum response at 1030 nm and the higher photosensitivity. Finally, the external quantum efficiency of the fabricated NIR photodetector was found to be 27%.