Thin Film Transistors Using Wafer-Scale Low-Temperature MOCVD WSe₂

We report on thin film transistors using continuous WSe₂ thin films synthesized by metal organic chemical vapor deposition at 400°C. O₂ plasma etching is used to provide precise thickness modification of the WSe₂ thin film with an etch rate ∼0.25 nm/min. Device performance is found to vary with the thickness of the WSe₂ films. P-channel thin film transistors with plasma-thinned 3 nm WSe₂ channels have mobility ∼0.01 cm²/Vs and current on–off ratio greater than 10⁴. Our results suggest that plasma etching may provide an approach for post-growth modification of the electrical properties of two-dimensional transition metal dichalcogenide thin films.