Influence of surface/interface stress on thermal conductivity of stressed GaN nanofilms

Abstract

This work investigates the effects of surface/interface stress on phonon thermal conductivity of stressed GaN nanofilms theoretically. The elasticity model is applied to describe the phonon dispersion relations of spatially confined GaN nanofilms. The acoustoelastic effects and surface/interface stress effects are accounted for in calculating the phonon properties and thermal conductivity. Theoretical results show that the surface/interface stress can alter significantly the phonon properties such as the phonon dispersion relations, resulting in the modification of thermal conductivity in GaN nanofilms. In addition, the surface/interface stress can change the dependence of thermal conductivity on the prestress fields and temperature. These results can be useful in controlling the thermal conductivity based on the strain/stress engineering in GaN nanostructures-based electronic devices.