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 110 K to 370 K. 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.