Bulk and few-layer MnPS3: a new candidate for field effect transistors and UV photodetectors

Layered metal thiophosphates with the general formula MPX3 (M is a group VI element and X is a chalcogen) have been emerging as a novel group of tunable bandgap semiconductors. Herein, we report the synthesis of high quality MnPS3 crystals, and their mechanical exfoliation onto pre-fabricated devices. The use of atomic force microscopy and Raman spectroscopy yielded information on the number of layers. MnPS3-based field effect transistors (FETs) comprising few-layer and bulk crystals with gold contacts show p-type conductivity with an on–off ratio of ∼103. Temperature dependent electrical transport measurements yield a Schottky barrier height value of 0.34 eV for few-layer devices. FETs based on multilayer and bulk MnPS3 show very similar transport characteristics. The transistor devices have also been shown to be good ultraviolet photodetectors with photoresponsivity of 288 A W−1 at a wavelength of 365 nm. Density functional theory calculations reveal the parameters that affect the viability of electron/hole doping in MnPS3 and help understand the p-type nature of the FET device.