Tailoring Contact Properties in Janus TMD Spin-FETs for Enhanced Spin Transport: A Bilayer Interface Approach

Janus transition metal dichalcogenides (TMDs) are promising two-dimensional (2D) semiconducting materials for spin field-effect transistor (spinFET) applications due to their strong spin–orbit coupling and broken out-of-plane inversion symmetry. However, maintaining a smooth interface between Janus TMDs and bulk ferromagnetic metals in spinFET is challenging due to the metal-induced gap states (MIGS) created by interface dangling bonds. In this study, we have shown that the insertion of an additional layer of Janus TMD as a buffer electrode between the ferromagnetic electrode and the Janus TMD channel effectively eliminates MIGS. Also, this buffer layer reduces the Schottky barrier height by creating a dipole moment at the interface between the top and bottom Janus TMD layers. Furthermore, the transition from n-type to p-type contact is achievable by altering the polarity of the interface dipole, which is associated with the direction of charge transfer at the metal–semiconductor interface. We also show that the tunneling probability of charge carriers can be enhanced by applying interlayer strain. Additionally, we find that the spin-polarization factor exceeds 60% at the ferromagnetic metal-bilayer Janus TMD interface, which is favorable for spin-polarized carrier transmission in spinFETs. Our results provide a roadmap for designing Janus TMD-based spinFETs for low-power, ultrafast neuromorphic device applications.