P-type conduction in two-dimensional MoS2 via oxygen incorporation

The effects of oxygen incorporation on the electronic transport properties of two-dimensional (2D) MoS2 have been studied via temperature dependent and gate voltage dependent transport measurements of physical vapor deposited 2D MoS2. Gated micro-van der Pauw cross devices were fabricated from the MoS2 film for transport measurements. Field-effect measurements indicate that incorporated oxygen acts as a p-type dopant for MoS2. The combination of X-ray photoemission spectroscopy surface analysis and Raman measurements the film indicates that acceptor states resulting from MoSxO3-x inclusions in the MoS2 film are the origin of the p-type doping. Temperature dependent van der Pauw conductivity measurements indicate an acceptor energy of 214 meV above the valence band edge for the acceptor state.