Temperature dependence of the thermal conductivity and phonon scattering time of a bulk GaN crystal

We have measured photothermal signals of a bulk GaN crystal by the photothermal divergence (PTD) method in the temperature range from 110K to 370K. The thermal conductivity and the scattering time of phonons contributing to the thermal conductivity have been evaluated from the, photothermal signals. A phonon-defect interaction has been expected to play a crucial role in determining the thermal properties of the sample employed here in the above temperature range.