Quantum transport simulations of monolayer β-AgI: a prospective nanochannel material in sub-1 nm gate-length MOSFETs

Abstract

Recently, two-dimensional (2D) monolayers of group-XI transition-metal halide MX (M = Cu, Ag; X = I) have been experimentally synthesized. Significant interest has been devoted to the monolayer (ML) MX due to their structural, mechanical, and thermodynamic stability and tunable band gap, greatly expanding the possibilities for exploring new 2D materials. Using an ab initio framework, we investigated the fundamental structural, dynamical, and electronic properties of pristine β-AgI ML. Considering the advantages of the structural and dynamical stability and tunable electronic band gap of β-AgI ML, we performed quantum transport simulations of a 0.34 nm gate-length double-gated metal–oxide–semiconductor field-effect transistor (MOSFET) providing an ultralow supply-voltage (V_dd = 0.54 V) while considering β-AgI ML as the nanochannel material. All the quantum transport simulations are done using the density functional theory (DFT) plus non-equilibrium Green's function (DFT + NEGF) approach within the Quantum-Atomistix ToolKit (Q-ATK) package. The performance limits of the pristine ML β-AgI for n- and p-type nanotransistors have been extensively studied for low-power (LP) and high-performance (HP) applications. We found that when considering a 2 nm underlap length, the performance limit of the 0.34 nm gate-length ML β-AgI double-gated p-type MOSFET meets the 2013 International Technology Roadmap for Semiconductors (ITRS) standards for LP and HP electronics applications projected for 2028. Based on our comprehensive analysis of quantum transport simulations, we believe that ML β-AgI has the potential to be used as a promising nanochannel material in MOSFETs, capable of miniaturizing and sustaining Moore's law scaling down to sub-1 nm gate-length transistors.