Electronic properties of monolayer tungsten disulfide grown by chemical vapor deposition

We demonstratechemical vapor deposition of largemonolayer tungsten disulfide (WS2) (>200  μm).Photoluminescence and Raman spectroscopy provide insight into the structural and strain heterogeneity of the flakes. We observe exciton quenching at grain boundaries that originate from the nucleation site at the center of the WS2 flakes.Temperature variable transportmeasurements of top-gated WS2transistors show an apparent metal-to-insulator transition. Variable range and thermally activated hopping mechanisms can explain the carrier transport in the insulating phase at low and intermediatetemperatures. The devices exhibit room-temperature field-effect electronmobility as high as 48  cm2/V.s. Themobility increases with decreasingtemperature and begins to saturate at below 100  °K, possibly due to Coulombscattering or defects.

Source: Applied Physics Letters - November 7, 2016 Category: Physics Authors: Abdullah Alharbi and Davood Shahrjerdi Source Type: research