Thermal conductivity of wide band gap nitrides from first principles calculations*

Wide band gap nitrides are of interest for applications in deep-UV optoelectronics and power electronics. Materials for these devices must be able to dissipate heat generated from operation, making thermal conductivity an important parameter for high-power applications. We have investigated the thermal conductivity of AlN, GaN, Al_xGa_1-xN and BN polymorphs with first-principles calculations, with a focus on effects from compositional and isotopic disorder. We use density functional theory to calculate the phonon frequencies and interatomic force constants. This information is used to calculate the thermal conductivity using the solution from the full Boltzmann transport equation calculation. Our results provide understanding on the benefits of using isotopically pure compositions in increasing the thermal conductivity of wide band gap nitrides.