S.L. Wong, D. Chi
A*STAR, Institute of Materials Research and Engineering, Singapore,
Keywords: transition metal dichalcogenides, MoS2, chemical vapor deposition, angle resolved photoemission spectroscopy
Summary:Transition metal dichalcogenides, in particular, MoS2, has attracted significant attention due to its unique electronic and physical properties. Much research efforts are directed towards achieving large area, high quality monolayer MoS2 films. Using NiO foam as a reactive barrier, we achieved growth of highly homogeneous single layer MoS2 on sapphire through chemical vapor deposition. As the NiO barrier reacts with MoO3, the concentration of precursors reaching the substrate and thus nucleation density is effectively reduced. By doing so, single crystal MoS2 grain sizes of up to 170 μm, together with continuous monolayers on the centimeter length scale are obtained. Angle-resolved photoemission spectroscopy measurements performed describe very well-resolved electronic band structure and spin orbit splitting of the bands at room temperature. Furthermore, the measurement reveals only two major domain orientations, indicating the successful growth of a highly crystalline and well-oriented MoS2 monolayer.