The effect of the dielectric environment on electrical and optical properties of monolayer molybdenum disulfide

Monolayer molybdenum disulfide (MoS$_{2})$ is a two-dimensional atomic crystal characterized by a direct band gap, strong electron-electron and spin-orbit interactions. Electron transport in currently available monolayer MoS$_{2}$ devices is dominated by strong Coulomb scattering limiting carrier mobility to \textless\ 200 cm$^{2}$/Vs. Here, we explore possible routes towards increasing carrier mobility in MoS$_{2}$. First, we investigate suspended ($\sim$200nm above Si/SiO$_{2})$ monolayer MoS$_{2}$ devices by combining electron beam lithography and an isotropic sacrificial etching of the underlying substrate. Second, we explore the mobility of MoS$_{2}$ devices fabricated on highly uniform hexagonal boron nitride (h-BN) crystals as a substrate material. Initial results indicate an order of magnitude increase in the electrical mobility using both approaches. Finally, we study MoS$_{2}$ devices embedded in a dielectric material with high dielectric constant and explore the interrelation between carrier mobility and dielectric constant.