Phonon Mean Free Path - Thermal Conductivity Relation in AlN

The challenging high temperature operation conditions for AlN based electronic devices such as UV LEDs and HEMTs may cause degradation and failure. In these applications, thermal conductivities of the material layers have a critical role in heat dissipation and device temperature reduction. Thermal conductivity and phonon mean free path calculations lead to better understanding of the thermal transport in such devices with small scales. This study aims to perform ab-initio calculations via VASP to obtain up to third-order force constants and feed them to Phono3py to calculate the phonons' contributions to the thermal conductivity of AlN. The results can be used to determine the onset of nanoscale thermal transfer in devices that consists of such materials and to determine a proper mean free path for nanoscale thermal simulations.