Better contact to WSe2 nanosheets

Nanomaterials The high electron and hole mobility of tungsten selenide (WSe2) nanosheets should make them ideal semiconductors for field-effect transistor (FET) devices, but with typical contact materials (silica layers on silicon and gold), mobilities, and on-off ratios fall to impractical levels. Stoeckel et al. functionalized one or both sides of WSe2 single-layer nanosheets with molecules containing silane groups. The tails of these molecules formed monolayers on the nanosheets, whereas the head groups formed monolayers on silica. These molecules also appeared to functionalize defect sites, and their presence changed the work function of the nanosheet and decreased the contact resistance to gold. High mobilities enabled unipolar and, for doubly-functionalized nanosheets, ambipolar FET operation in devices with gold top contacts. ACS Nano 10.1021/acsnano.9b05423 (2019).