High thermal conductivity is an important parameter for nitride-based power electronic and deep-UV light emitters. Especially in the latter case short period superlattices and multicomponent alloys are used and the knowledge of the thermal properties of the binary compounds is sufficient. In-plane and cross-plane thermal conductivity of AlGaN/GaN superlattices were measured by differential two-wire 3ω method in the temperature range from 147 to 325 K. Samples were grown by metalorganic vapor phase epitaxy; the structure quality and accuracy of superlattice structures preparation were verified by means of HRXRD and transmission electron microscopy. It was observed, that value of thermal conductivities decrease with decreasing period thickness, while temperature dependencies differ from each other—in-plane thermal conductivity decreases, and cross-plane—increases with increasing temperature. Callaway method was used for thermal conductivity calculation; dependence of boundary scattering rate on the phonon wavelength was taken into account. Minimum thermal conductivity was added to calculated values to include the influence of high frequency acoustic phonons and optical phonons on the heat transport. Calculations are in good agreement with experimental results.

No abstract

No abstract

Herein, the results of theoretical investigation of anisotropic thermal conductivity of AlGaN/GaN superlattices (SLs) are presented. For calculations, the Boltzmann transport equation in the relaxation time approximation is used. Results of computations are compared with experiment and theoretical result obtained using Callaway model. Good agreement between experimental and theoretical results is observed. Opportunity of use of the Callaway model for calculation of anisotropic thermal conductivity of SLs is discussed.