High-performance 5.1 nm in-plane Janus WSeTe Schottky barrier field effect transistors

Abstract

Using ab initio quantum-transport simulations, we studied the intrinsic transfer characteristics and benchmarks of the ballistic performance of 5.1 nm double-gated Schottky-barrier field effect transistors (SBFETs) consisting of in-plane (IP) heterojunctions of metallic-phase (1T or 1T′) MTe₂ (M = Ti, Zr, Hf, Cr, Mo, W) and semiconducting-phase (2H) WSe₂, WTe₂ and Janus WSeTe. The 2H-phase Janus WSeTe is a semiconductor with an indirect bandgap (1.26 eV), which is less than the bandgap of 2H-phase WSe₂ (1.64 eV) and is greater than the bandgap of 2H-phase WTe₂ (1.02 eV). The band alignments show that all IP 1T/2H contacts are Schottky-barrier contacts with the Fermi levels of 1T or 1T′ MTe₂ (M = Ti, Zr, Hf, Cr, Mo, W) located within the bandgaps of 2H WSe₂, WTe₂ and Janus WSeTe. Although double-gated IP WSe₂-SBFETs can satisfy the OFF current requirement, their ON currents all fall below the requirements of the high performance transistor outlined by the ITRS (International Technology Roadmap for Semiconductors, 2013 version) for the production year 2028. Double-gated IP WTe₂-SBFETs cannot overcome the short channel effect leading to minimum drain currents all beyond the OFF current requirement of ITRS (2013 version) for the production year 2028. Fortunately, double-gated IP WSeTe-SBFETs with 1T MoTe₂ or 1T′ WTe₂ electrodes can overcome the short channel effect and satisfy the requirements of the high-performance transistor outlined by the ITRS (2013 version) for the production year 2028.