FeB 2 monolayer as Dirac semimetal electrode for Ohmic contact with two-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 semiconductors, owing to their high in-plane conductivity, weak metallization at the interface and work function tunability by gate voltages and strains. Herein, we investigate the potential of a Dirac semi-metal FeB 2 as high performance electrode material using density functional theory. We study its interfaces with transition metal dichalcogenide (TMDs: MoS 2 , WS 2 ) and Janus TMD (JTMDs: MoSSe , WSSe ) semiconductors. We construct novel van der Waals metal-semiconductor interfaces by stacking FeB 2 monolayer on top of semiconductor layers and systematically examine the effects of stacking order and external electric fields on their electronic properties. We show that electric coupling between FeB 2 and semiconducting layers result in ultra-low n-type and p-type Schottky barriers. These barriers are sensitive to both electric fields and stacking, enabling transitions between n-type, p-type and Ohmic contacts. Additionally, the interfaces exhibit ultralow tunneling resistivity, offering favorable balance between Schottky and tunneling barriers. The efficient barrier control and minimal tunneling resistances are in line with International Roadmap for Devices and Systems standards. These findings expand the Dirac semi-metal family as a high quality contact and provide comprehensive theoretical insights for developing future sub-nm scaled FETs utilizing FeB 2 .