Electronic transport properties of two-dimensional tetragonal zinc chalcogenides.

The electronic transport properties of two-dimensional (2D) tetragonal ZnX (X = S, Se) monolayers have been studied using density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. The gate voltage (a 5 V in particular) generally enhances the transport performance of the monolayers, which is ca. three times that without the gate voltage. It is shown that the transport properties of the Janus Zn 2 SeS monolayer may show a relatively good trend among the ZnX monolayers, and the Zn 2 SeS monolayer has the highest sensitivity to gate-voltage regulation. We also investigate the photocurrent of ZnX monolayers under linearly polarized light irradiation in the visible and near-ultraviolet regions, and the ZnS monolayer processes a maximum value of 15 a 0 2 per photon in the near-ultraviolet region. The excellent electronic transport properties make environmentally friendly tetragonal ZnX monolayers promising for utilization in various electronic and optoelectronic devices.