论文标题
为什么二维半导体通常具有低电子迁移率
Why Two-Dimensional Semiconductors Generally Have Low Electron Mobility
论文作者
论文摘要
原子上薄（二维2D）半导体作为下一代电子产品的基本构建块表现出很大的潜力。但是，到目前为止，所有经过实验制造的2D半导体的室温电子迁移率低于散装硅的室温，这尚不清楚。在这里，通过使用第一原理计算并重新设计传输方程来隔离和量化不同迁移率定义因素的贡献，我们表明，2D半导体的普遍较低的迁移率源自具有寄生虫电子带对2D材料的高“散射密度”。散射的密度表征了可以与电子相互作用的声子的密度，并且可以从电子和声音带结构完全确定，而无需了解电子偶联强度。我们的工作揭示了限制2D半导体电子移动性的潜在物理学，并提供了描述符来快速评估移动性。
Atomically thin (two-dimensional, 2D) semiconductors have shown great potential as the fundamental building blocks for next-generation electronics. However, all the 2D semiconductors that have been experimentally made so far have room-temperature electron mobility lower than that of bulk silicon, which is not understood. Here, by using first-principles calculations and reformulating the transport equations to isolate and quantify contributions of different mobility-determining factors, we show that the universally low mobility of 2D semiconductors originates from the high 'density of scatterings,' which is intrinsic to the 2D material with a parabolic electron band. The density of scatterings characterizes the density of phonons that can interact with the electrons and can be fully determined from the electron and phonon band structures without knowledge of electron-phonon coupling strength. Our work reveals the underlying physics limiting the electron mobility of 2D semiconductors and offers a descriptor to quickly assess the mobility.
