FeB 2 monolayer as Dirac semimetal electrode for Ohmic contact withtwo-dimensional MXY (M = Mo or W; X, Y = S or Se) semiconductors

Abstract Dirac semi-metals have emerged as excellent metal electrodes for two-dimensional semi-conductors, owing to their high in-plane conductivity, weak metallization at the interface andwork function tunability by gate voltages and strains. Herein, we investigate the potentialof a Dirac semi-metal FeB 2 as high performance electrode material using density functionaltheory (DFT). We study its interfaces with transition metal dichalcogenide (TMDs: MoS 2 ,WS2) and Janus transition metal dichalcogenide (JTMDs: MoSSe, WSSe) semiconductors.We construct novel van der Waals metal-semiconductor interfaces (vdW-MSIs) by stackingFeB 2 monolayer on top of semiconductor layers and systematically examine the effects ofstacking order and external electric fields on their electronic properties. We show that elec-tric coupling between FeB 2 and semiconducting layers result in ultra-low n-type and p-typeSchottky barriers. These barriers are sensitive to both electric fields and stacking, enablingtransitions between n-type, p-type and Ohmic contacts. Additionally, the interfaces exhibitultralow tunneling resistivity, offering favorable balance between Schottky and tunnelingbarriers. The efficient barrier control and minimal tunneling resistances are in line withInternational Roadmap for Devices and Systems(IRDS) standards. These findings expandthe Dirac semi-metal family as a high quality contact and provide comprehensive theoreticalinsights for developing future sub-nm scaled FETs utilizing FeB 2 .