  Two-dimensional MoS2 has emerged as promising material for nanoelectronics
and spintronics due to its exotic properties. However, high contact resistance
at metal semiconductor MoS2 interface still remains an open issue. Here, we
report electronic properties of field effect transistor devices using monolayer
MoS2 channels and permalloy (Py) as ferromagnetic (FM) metal contacts.
Monolayer MoS2 channels were directly grown on SiO2/Si substrate via chemical
vapor deposition technique. The increase in current with back gate voltage
shows the tunability of FET characteristics. The Schottky barrier height (SBH)
estimated for Py/MoS2 contacts is found to be +28.8 meV (zero-bias), which is
the smallest value reported so-far for any direct metal (magnetic or
non-magnetic)/monolayer MoS2 contact. With the application of gate voltage (+10
V), SBH shows a drastic reduction down to a value of -6.8 meV. The negative SBH
reveals ohmic behavior of Py/MoS2 contacts. Low SBH with controlled ohmic
nature of FM contacts is a primary requirement for MoS2 based spintronics and
therefore using directly grown MoS2 channels in the present study can pave a
path towards high performance devices for large scale applications.
