Device Performance Assessment of Monolayer HfSe2: A New Layered Material Compatible With High- $\kappa$ HfO2

HfSe₂ is an attractive 2-D material for electronic devices due to the existence of natively compatible HfO₂. Using density functional theory and the non-equilibrium Green's function, we have explored monolayer HfSe₂ for device applications. Despite different effective masses and asymmetric density of states in the conduction and valence bands, interestingly, both n-type and p-type devices exhibit nearly identical transfer characteristics with large ON-current (>1 mA/μm), steep switching (<;70 mV/dec), and high ON/OFF current ratio (> 10⁷). According to our scaling study with channel length (L_ch) and oxide thickness variations, HfSe₂ FETs exhibit great immunity to short-channel effects at L_ch ≥ 15 nm but show significant degradations in subthreshold swing and drain-induced barrier lowering at sub-10-nm channel even with a thin gate dielectric. We further evaluated the intrinsic performances of HfSe₂ FETs and revealed the promising potential of HfSe₂ for logic devices considering both speed and power dissipation simultaneously.