Designing Power-Efficient Transistors Using Narrow-Bandwidth Materials from the MA2Z4 (M=Mo, Cr, Zr, Ti, Hf; A=Si, Ge; Z=N, P, As) Monolayer Series

The subthreshold leakage current in transistors has become a critical limiting factor for realizing ultralow-power transistors. The leakage current is predominantly dictated by the long thermal tail of the charge carriers. We propose a solution to this problem by using narrow-bandwidth semiconductors to limit the thermionic leakage current by filtering out the high-energy carriers. We specifically demonstrate this solution in transistors with a laterally confined ${\text{MoSi}}_{2}{\text{N}}_{4}$ monolayer with different passivation serving as channel material. Remarkably, we find that the proposed narrow-bandwidth devices can achieve a large on:off current ratio with an ultralow-power supply voltage of $\ensuremath{\sim}0.1\phantom{\rule{0.2em}{0ex}}\text{V}$, even for devices with $\ensuremath{\sim}5\phantom{\rule{0.2em}{0ex}}\mathrm{nm}$ gate length. We also show that several other materials share the unique electronic properties of narrow-bandwidth conduction and valence bands in the same series.