Silicon Nanowire Conductance in the Ballistic Regime: Models and Simulations

This study deals with phonon heat transport in silicon nanowires. A review of various methods that can be used to assess thermal conductance of such nanodevices is presented. Here, a specific attention is paid to the case of the Landauer Formalism, which can describe extremely thin wires conductance. In order to use this technique, the calculation of propagating modes in a silicon nanowire is necessary. Among the several existing models allowing such calculation, the elastic wave theory has been used to obtain the normal mode number. Besides, in this study, the transmission and reflection of phonon at the interface between two nanostructures are discussed. Using the diffuse mismatch model (DMM), the global transmissivity of the system made of a nanowire suspended between two thermal reservoirs is addressed. Then, the calculations of normal modes’ numbers and thermal conductances of several silicon nanowires, with various diameters set between bulk thermal reservoirs, are presented and compared to other models and available experiments.