Tuning The Conductivity Type In Monolayer Ws(2)And Mos(2)By Sulfur Vacancies

Whilen-type behavior appears to be more common in as-prepared two-dimensional (2D) transition metal dichalcogenides (TMDCs), substitutional doping with electron accepting atoms is typically required to tune the conductivity top-type in order to facilitate their potential application in different devices. Herein, a systematic study is reported on the equivalent electrical "doping" effect of single sulfur vacancies (V-1S) in monolayer WS(2)and MoS(2)by studying the interface interaction of WS2-Au and MoS2-Au contacts. Based on the first principles calculations, it is found that the V(1S)can significantly alter the semiconductor behavior of both monolayer WS(2)and MoS(2)so that they can exhibit the character of electron acceptor (p-type) as well as electron donor (n-type) when they are contacted with gold. For relatively low V(1S)densities (approximately <7% for MoS(2)and <3% for WS2), the monolayer TMDC serves as electron acceptor. As the V(1S)density increases beyond the threshold densities, the MoS(2)and WS(2)play the role of electron donor. The significant impact V(1S)can have on monolayer WS(2)and MoS(2)may be useful for engineering its electrical behavior and offers an alternative way to tune the semiconductor TMDCs to exhibit eithern-type orp-type behavior.