Two-dimensional (2D) $\mathrm{Ge}\mathrm{Te}$ exhibits excellent interface compatibility with $\mathrm{Si}/{\mathrm{Si}\mathrm{O}}_2$ substrates, which makes it a promising channel material for field-effect transistors beyond the silicon-based era. A recent study has indicated the viability of the exfoliation of 2D $\mathrm{Ge}\mathrm{Te}$ to monolayer (ML) thickness utilizing liquid-phase methodologies assisted by sonication. This study applies ab initio quantum transport simulations to investigate the device performance limits of sub-5-nm ML $\mathrm{Ge}\mathrm{Te}$ metal-oxide-semiconductor field-effect transistors (MOSFETs). The on-state current, subthreshold swing, switching speed, and power consumption of n- and p-type ML $\mathrm{Ge}\mathrm{Te}$ MOSFETs in both the zigzag and armchair orientations are explored. No significant anisotropy is observed. Along the zigzag and armchair directions, the optimized n-type $\mathrm{Ge}\mathrm{Te}$ transistors can well satisfy the key criteria of the International Technology Roadmap for Semiconductors for high-performance applications at a 3-nm gate length, and for low-power applications at a 5-nm gate length. The performance of the n-type transistor exceeds that of the p-type one. The ML $\mathrm{Ge}\mathrm{Te}$ MOSFETs along the zigzag and armchair directions with gate length of 5 nm possess on-state current levels reaching up to 2452 and 1917 µA/µm, accompanied by corresponding energy-delay products $6.24\times {10}^{-30}$ and $2.35\times {10}^{-29}$ Js/µm, respectively, surpassing many other 2D MOSFETs. Our work demonstrates that ML $\mathrm{Ge}\mathrm{Te}$ as a channel candidate can help push Moore’s law down to the sub-5-nm regime.

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• Electrical conductivity
• Quantum transport
• 2-dimensional systems
• Device fabrication
• Field-effect transistors
• Semiconductor compounds
• Density functional calculations
• Nonequilibrium Green's function