Two-dimensional (2D) semiconductors are promising channel materials for next-generation field-effect transistors (FETs) thanks to their unique mechanical properties and enhanced electrostatic control. However, the performance of these devices can be strongly limited by the scattering processes between carriers and phonons, usually occurring at high rates in 2D materials. Here, we use quantum transport simulations calibrated on first-principle computations to report on dissipative transport in antimonene and arsenene n-type FETs at the scaling limit. We show that the widely-used approximations of either ballistic transport or simple acoustic deformation potential scattering result in large overestimation of the ON current, due to neglecting the dominant intervalley and optical phonon scattering processes. We additionally investigate a recently proposed valley engineering strategy to improve the device performance by removing the valley degeneracy and suppressing most of the intervalley scattering channels via an uniaxial strain along the zigzag direction. The method is applicable to other similar 2D semiconductors characterized by multivalley transport.

由于其独特的机械性能和增强的静电控制，二维 (2D) 半导体是下一代场效应晶体管 (FET) 的有前途的沟道材料。然而，这些器件的性能会受到载流子和声子之间的散射过程的强烈限制，通常在二维材料中以高速率发生。在这里，我们使用基于第一性原理计算校准的量子传输模拟来报告锑烯和砷烯n 中的耗散传输型 FET 处于缩放限制。我们表明，由于忽略了主要的间隔和光学声子散射过程，广泛使用的弹道传输或简单声学变形势散射的近似值导致对导通电流的高估。我们还研究了最近提出的谷工程策略，以通过沿锯齿形方向的单轴应变消除谷简并和抑制大部分间隔散射通道来提高器件性能。该方法适用于其他类似的以多谷传输为特征的二维半导体。