A first principles method to simulate electron mobilities in 2D materials

Abstract

We examine the predictive capabilities of first-principles theoretical methods to calculate the phonon- and impurity-limited electron mobilities for a number of technologically relevant two-dimensional materials in comparison to experiment. The studied systems include perfect graphene, graphane, germanane and MoS _2 , as well as graphene with vacancies, and hydrogen, gold, and platinum adsorbates. We find good agreement with experiments for the mobilities of graphene ( μ = 2 × 10 ^5 cm ^2 V ^−1 s ^−1 ) and graphane ( μ = 166 cm ^2 V ^−1 s ^−1 ) at room temperature. For monolayer MoS _2 we obtain μ = 225 cm ^2 V ^−1 s ^−1 . This value is higher than what is observed experimentally (0.5–200 cm ^2 V ^−1 s ^−1 ) but is on the same order of magnitude as other recent theoretical results. For bulk MoS _2 we obtain μ = 48 cm ^2 V ^−1 s ^−1 . We obtain a very high mobility of 18 200 cm ^2 V ^−1 s ^−1 for single-layer germanane. The calculated reduction in mobility from the different impurities compares well to measurements where experimental data are available, demonstrating that the proposed method has good predictive capabilities and can be very useful for validation and materials design.

Keywords

• electron mobility
• 2D materials
• density functional theory
• nanoscience
• computational modeling