Approaching barrier-free contacts to monolayer MoS2 employing [Co/Pt] multilayer electrodes

Abstract

The broken inversion symmetry and time-reversal symmetry along with the large spin–orbit interactions in monolayer MoS2 make it an ideal candidate for novel valleytronic applications. However, the realization of efficient spin-valley-controlled devices demands the integration of perpendicular magnetic anisotropy (PMA) electrodes with negligible Schottky barriers. Here, as the first demonstration, we fabricated a monolayer MoS2 field-effect transistor with PMA electrodes: Pt/[Co/Pt]3 and [Co/Pt]2. The I–V curves of PMA/MoS2 contacts show symmetric and linear behavior reflecting Ohmic nature. The flat-band Schottky barrier heights (SBHs) extracted using the temperature and gate voltage dependence of the I–V curves were found to be 10.2 and 9.6 meV. The observed SBHs are record low values reported thus far for any metal/monolayer MoS2 contact. High-quality PMA electrodes with almost zero SBH play a paramount role in the future development of novel spintronic/valleytronic devices; hence, our results can open a new route toward the realization of novel technological devices employing two-dimensional materials.