Nanoscale heat transfer: Investigating size effects on thermal conductivity in thin films

Abstract

This study investigates the size-dependent thermal conductivity of nanofilms utilizing a theoretical model that incorporates the effects of dangling bonds on the surfaces, critical size, and characteristic dimensions. The model integrates Qi's thermodynamical approach and Kumar's work with the Yang model to develop a novel expression for size dependence of thermal conductivity. This investigation applies the model to copper and silicon nanofilms and compares the results with experimental data. These findings demonstrate that the thermal conductivity decreases with decreasing thickness, particularly below 150 nm. The theoretical curves exhibited strong alignment with the experimental data, validating the efficacy of the model. The study concludes that the proposed model is adequate for elucidating the thermal conductivity of nanomaterials and can be used to predict materials that lack experimental data. The model's capacity to account for size effects and surface phenomena renders it valuable for understanding the thermal properties of nanomaterials, which are crucial for their application in electronics, energy, and thermal management.