Layer-Dependent Optoelectronic Properties of 2D van der Waals SnS Grown by Pulsed Laser Deposition

Layered metal monochalcogenides have attracted significant interest in the 2D family since they show different unique properties from their bulk counterparts. The comprehensive synthesis, characterization, and optoelectrical applications of 2D-layered tin monosulfide (SnS) grown by pulsed laser deposition are reported. Few-layer SnS-based field-effect transistors (FETs) and photodetectors are fabricated on Si/SiO2 substrates. The premium 2D SnS FETs yield an on/off ratio of 3.41 x 10(6), a subthreshold swing of 180 mV dec(-1), and a field effect mobility (mu(FE)) of 1.48 cm(2) V-1 s(-1) in a 14-monolayer SnS device. The layered SnS photodetectors show a broad photoresponse from ultraviolet to near-infrared (365-820 nm). In addition, the SnS phototransistors present an improved detectivity of 9.78 x 10(10) cm(2) Hz(1/2) W-1 and rapid response constants of 60 ms for grow-time constant tau(g) and 10 ms for decay-time constant tau(d) under extremely weak 365 nm illumination. This study sheds light on layer-dependent optoelectronic properties of 2D SnS that promise to be important in next-generation 2D optoelectronic devices.