Annealing and ionic liquid gating on suspended molybdenum disulfide devices

We fabricate suspended molybdenum disulfide (MoS$_{\mathrm{2}})$ field effect transistors (FET) devices and develop an effective gas annealing technique that significantly improves device quality and increases conductance by 3-4 orders of magnitude.~Temperature dependence measurements reveal two transport mechanisms: electron-phonon scattering at high temperatures and thermal activation over a gate-tunable barrier height at low temperatures. Our results suggest that transport in these devices is not limited by the substrates. Moreover,~this suspended MoS$_{\mathrm{2}}$~device structure provides double surface access for ionic liquid gating. We are able to extract the dielectric constant of the ionic liquid, and the~latest experimental results will be presented.