Thermal conductivity and heat transport properties of graphene nanoribbons

Abstract

The graphene nanoribbons (GNRs) are promising candidate for next-generation electronic materials. Herein, the thermal conductivity (TC) and heat transport properties of GNRs were investigated as a function of temperature and nanoribbon size using equilibrium molecular dynamics simulation based on Green–Kubo method. According to the results, by increasing temperature, the TC decreases monotonically by T −1.52. The size dependence of TC was studied using a series of GNRs with 2 nm in width and 2–30 nm in length. The results showed that the TC decreases with longitudinal extension to reach a plateau at ~1,500 W m−1 K−1 based on an exponential curve fitting. The phonon scattering relaxation time, the average group velocity of phonons, and the phonon mean free paths were also calculated. The contribution of high frequency optical phonons to the total TC is negligible (0.3–2.0 %) below 400 K and exponentially increases at higher temperatures. When the quantum corrections for temperature were considered to the calculated results, the maximum value for TC (~5,500 W m−1 K−1) was obtained at 130 K.