The impact of hydrogenation on the thermal transport of silicene

Abstract

Silicene, the silicon counterpart of graphene, has been identified as a promising 2D material for electronics applications. The reported very low thermal conductivity of silicene can potentially pose challenges on the thermal management of such nanoelectronics, which can in turn influence the device performance and reliability. Although the thermal conductivity of silicene has been studied, the impact of hydrogenation of silicene, which can happen spontaneously due to the resultant lower energy state, on its thermal transport ability is not clear. In this paper, we use first-principles calculations and iterative solution of phonon Boltzmann transport equation (BTE) to investigate and compare the thermal transport property of silicene and hydrogenated silicene. Surprisingly, we predict that the hydrogenation can lead to a large increase in thermal conductivity (from 22.5 W m−1 K−1 for silicene to 78.0 W m−1 K−1 for hydrogenated silicene at 300 K). We also find that the main contributor for such an improvement is the transverse acoustic phonon modes, and the reasons are the reduced anharmonicity as well as the reduced three-phonon scattering phase space after hydrogenation. This research may help better understand thermal transport in functionalized 2D materials and inspire new strategies to manipulate their thermal properties, which is of critical importance for designing high performance and reliable nanoelectronic devices.