Photoresponsive field-effect transistors based on multilayer SnS2 nanosheets

2D SnS2 nanosheets are exfoliated by micromechanical exfoliation technique from SnS2 single crystals which are synthesized by CVT methods. Monolayer SnS2 nanosheet has been obtained and the Raman spectrum shows that A1g mode of monolayer SnS2 shows a slight softening compared with bulk SnS2 single crystal. The field effect transistors (FETs) based on multilayer SnS2 nanosheets have been fabricated, of which the electrical and photoelectrical properties have been measured. Under dark condition, with Vsd of 1 V, our SnS2 FET shows n-type behavior. The carrier mobility of the FETs reach 3.51 cm(2)V(-1)s(-1) and the 'ON/OFF' ratio is about 5 x 10(2). The SnS2 FET is also illuminated under 532 nm laser with the power of 500 mW/cm(2). The light absorption causes an increment of carrier mobility (from 3.51 cm(2)V(-1)s(-1) under dark condition to 3.85 cm(2)V(-1)s(-1) under 532 nm laser illumination with the power of 500 mW/cm(2)/of SnS2. The responsivity (R) and detectivity of our multilayer device under 500 mW/cm(2) 532 nm is 2.08 A/W and 6 x 10(6) J, respectively. All the above properties indicate the potential of SnS2 nanosheets to be used as FETs and phototransistors.