Department of Materials , University of Oxford , Parks Road , Oxford , OX1 3PH , United Kingdom.
Nano Lett. 2019 Mar 13;19(3):1774-1781. doi: 10.1021/acs.nanolett.8b04799. Epub 2019 Feb 12.
Two-dimensional (2D) semiconductors are at the center of an intense research effort aimed at developing the next generation of flexible, transparent, and energy-efficient electronics. In these applications, the carrier mobility, that is the ability of electrons and holes to move rapidly in response to an external voltage, is a critical design parameter. Here, we show that the interlayer coupling between electronic wave functions in 2D semiconductors can be used to drastically alter carrier mobility and dynamics. We demonstrate this concept by performing state-of-the-art ab initio calculations for InSe, a prototypical 2D semiconductor that is attracting considerable attention, because of its exceptionally high electron mobility. We show that the electron mobility of InSe can be increased from 100 cm V s to 1000 cm V s by exploiting the dimensional crossover of the electronic density of states from two dimensions to three dimensions. By generalizing our results to the broader class of layered materials, we discover that dimensionality plays a universal role in the transport properties of 2D semiconductors.
二维（2D）半导体是目前研究的热点，旨在开发下一代柔性、透明、节能的电子产品。在这些应用中，载流子迁移率（即电子和空穴在外加电压下快速移动的能力）是一个关键的设计参数。在这里，我们展示了 2D 半导体中电子波函数的层间耦合可以用来显著改变载流子迁移率和动力学。我们通过对二维半导体的典型代表 InSe 进行最先进的第一性原理计算来证明这一概念，由于其极高的电子迁移率，InSe 引起了广泛的关注。我们表明，通过利用电子态密度从二维到三维的维度交叉，可以将 InSe 的电子迁移率从 100 cm V s 提高到 1000 cm V s。通过将我们的结果推广到更广泛的层状材料类，我们发现维度在二维半导体的输运性质中起着普遍的作用。
