Determination of thermal properties of unsmooth Si-nanowires

In this work, we estimate the thermal properties of unsmooth Si-nanowires, considering key factors such as size (diameter), surface texture (roughness), and quantum size effects (phonon states) at different temperatures. For nanowires with a diameter smaller than 20 nm, we highlight the importance of quantum size effects in heat capacity calculations, using dispersion relations derived from the modified frequency equation for the elasticity of rod. The thermal conductivities of nanowires with diameters of 37, 56, and 115 nm are predicted using the FuchsSondheimer model and Soffer’s specular parameter. Notably, the roughness parameters are chosen to reflect the technological characteristics of the real surfaces. Our findings reveal that surface texture plays a significant role in thermal conductivity, particularly in the realm of ballistic heat transfer within nanowires. This study provides practical recommendations for developing new thermal management materials.