High Mobility Ambipolar MoS2 Field-Effect Transistors: Substrate and   Dielectric Effects
  We fabricate MoS2 field effect transistors on both SiO2 and polymethyl methacrylate (PMMA) dielectrics and measure charge carrier mobility in a four-probe configuration. For multilayer MoS2 on SiO2, the mobility is 30-60 cm2/Vs, relatively independent of thickness (15-90 nm), and most devices exhibit unipolar n-type behavior. In contrast, multilayer MoS2 on PMMA shows mobility 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 points to a long-range dielectric effect of the bulk MoS2 in increasing mobility. 
Wenzhong Bao, Xinghan Cai, Dohun Kim, Karthik Sridhara, and Michael S.   Fuhrer
cond-mat.mes-hall cond-mat.mtrl-sci