Simulating stress-tunable phonon and thermal properties in heterostructured AlN/GaN/AlN-nanofilms

Abstract

The acoustic phonon and thermal properties of GaN-based heterostructured nanofilms are investigated theoretically considering the effects of quantum confinement and prestress fields. The continuum elastic model is utilized to derive the acoustic phonon dispersion relations of GaN-based nanofilms in which the prestress fields are taken into account. The numerical results demonstrate that prestress fields can alter acoustic phonon properties significantly, such as dispersion relation and phonon group velocities. The trend of variation turns to be opposite as the direction of prestress fields reverses. The change of phonon properties under various prestress fields is sensitive to the thickness of core layer in heterostructured nanofilms. Moreover, the modification of acoustic phonon properties in heterostructured nanofilms under prestress fields gives rise to the change of phonon thermal conductivities for different phonon modes. Moreover, prestress fields can modify the influence of temperature-dependent phonon thermal conductivity of GaN-based heterostructured nanofilms. The results in this work could be helpful for the thermal management and rational design of high-performance in nano/microelectronic devices.