Thermal conductivity of GaN

Thermal conductivity (TC) data on wurtzite GaN samples, in literature, covering a wide temperature range (4.2-400 K), are analyzed employing two models; one due to Holland and another a modified Callaway model. Scattering of phonons by sample boundaries, impurities, dislocations and other phonons via both normal and umklapp processes is considered. A good representation of the temperature dependence, in all the samples considered, is obtained with a single set of phonon-phonon scattering parameters. The parameters are found to be reasonable and consistent with values in other systems. The parameters characterizing the scattering by various imperfections are also determined. The analyses presented bring out the relative importance of the phonon scattering mechanisms and the characteristic temperature dependencies operative in GaN. A need for inclusion of more realistic phonon dispersion and relaxation times is pointed out. (c) 2006 Elsevier B.V. All rights reserved.