Enhanced Hole Injection Into Single Layer WSe2

Electronic devices with light-emitting regions composed of single layer transition metal dichalcogenides, such as tungsten diselenide (WSe
₂
), are of great interest due to the formation of a direct bandgap at the single layer limit. Furthermore, increasing injected hole current into the single layer WSe
₂
is of great importance due to the resulting increase in electroluminescence. In this paper, we demonstrate a 1000× increase in injected hole current into the channel region of an FET composed of a single layer WSe
₂
channel by incorporation of a thicker (20-30 nm) multilayer WSe
₂
film under the metal source contact only. By fabrication and analysis of FETs composed of single layer, bi-layer, and tri-layer WSe
₂
channel regions, we correlate the increase in injected hole current to a decrease in the hole Schottky barrier height at the source contact due to incorporation of the multilayer WSe
₂
film.