Anomalous effect of hydrogenation on phonon thermal conductivity in thin silicon nanowires

Using equilibrium molecular-dynamics simulations, we investigate the phonon thermal conductivity of hydrogenated silicon nanowires (H-SiNWs). In contrast to the usual thermal conductivity reduction observed upon surface passivation due to the enhancement of phonon-surface scattering in nanostructures, we observe increased thermal conductivity upon the surface hydrogenation of thin SiNWs as compared to pure SiNWs. We show that such an anomalous effect arises mainly from the hydrogenation-induced specific changes in the lattice structures and phonon modes of surface silicon atoms. © Copyright EPLA, 2014.