Substrate dependence of Hall and Field-effect mobilities in few-layer MoS$_{2}$ field-effect transistors*

In this work, we systematically study the Hall and field-effect mobilities of few-layer MoS$_{2}$ FETs fabricated on different substrates. Hall bar devices were fabricated on SiO$_{2}$ and hBN to directly measure carrier density. Standard four-probe transport measurement and Hall effect measurement were carried out for a wide temperature range to determine the carrier mobility and understand the scattering mechanisms. By comparing field-effect and Hall mobilities, we demonstrate that the intrinsic drift mobility of multiplayer MoS$_{2}$ in the high carrier density metallic region is independent of substrate and sample thickness. While the optical-phonon scattering remains the dominant scattering mechanism in MoS$_{2}$ devices on h-BN down to \textasciitilde 100 K, extrinsic scattering mechanisms start to degrade the carrier mobility of MoS$_{2}$ on all other substrates below \textasciitilde 200 K.