MXene alloy-based metal-semiconductor contact for low-resistive field-effect transistors.

MXenes offer a unique platform for designing high-performance electronic devices due to their diverse properties and chemical tunability. This study focuses on engineering low-resistance metal-semiconductor contacts using MXenes for future field-effect transistor applications. Through a comprehensive approach combining first-principles calculations, transport simulations, and alloy phase engineering, we demonstrate the feasibility of achieving low-resistance contacts with high current-carrying capacity. Through first-principles calculations, we identify promising MXene heterojunctions based on lattice matching and Schottky barrier height. Notably, the Ta2CO2-Ti2CO2 contact exhibits a remarkably low Schottky barrier height. Using non-equilibrium Green's function calculations, we demonstrate high output current in this contact, indicating low resistance. Further analysis reveals the critical role of carrier density and detrimental impact of metal-induced gap states. To suppress metal-induced gap states, we propose an interfacial alloying strategy using a Ta2xTi2(1-x)CO2 solid solution, which reduces interfacial charge transfer and promotes smoother electronic coupling. This, in turn, reduces the Fermi-level pinning effect and contributes to a substantial reduction in contact resistance across the MXene interface. This study highlights the potential of MXenes as building blocks for advanced electronics and provides a pathway for engineering high-performance contacts through a combined computational and design approach.