High Mobility Ambipolar MoS2 Field-Effect Transistors: Substrate and Dielectric Effects

摘要

We fabricate MoS2 field effect transistors on both SiO2 and polymethylmethacrylate (PMMA) dielectrics and measure charge carrier mobility in afour-probe configuration. For multilayer MoS2 on SiO2, the mobility is 30-60cm2/Vs, relatively independent of thickness (15-90 nm), and most devicesexhibit unipolar n-type behavior. In contrast, multilayer MoS2 on PMMA showsmobility increasing with thickness, up to 470 cm2/Vs (electrons) and 480 cm2/Vs(holes) at thickness ~50 nm. The dependence of the mobility on thickness pointsto a long-range dielectric effect of the bulk MoS2 in increasing mobility.