Controllable Schottky Barriers between MoS(2) and Permalloy

MoS(2) is a layered two-dimensional material with strong spin-orbit coupling and long spin lifetime, which is promising for electronic and spintronic applications. However, because of its large band gap and small electron affinity, a considerable Schottky barrier exists between MoS(2) and contact metal, hindering the further study of spin transport and spin injection in MoS(2). Although substantial progress has been made in improving device performance, the existence of metal-semiconductor Schottky barrier has not yet been fully understood. Here, we investigate permalloy (Py) contacts to both multilayer and monolayer MoS(2). Ohmic contact is developed between multilayer MoS(2) and Py electrodes with a negative Schottky barrier, which yields a high field-effect mobility exceeding 55 cm(2)V(−1)s(−1) at low temperature. Further, by applying back gate voltage and inserting different thickness of Al(2)O(3) layer between the metal and monolayer MoS(2), we have achieved a good tunability of the Schottky barrier height (down to zero). These results are important in improving the performance of MoS(2) transistor devices; and it may pave the way to realize spin transport and spin injection in MoS(2).