The temperature dependence of the thermal conductivity of single crystal GaN films

The thermal conductivity of both LEO and HVPE single crystals of GaN have b een measured over the temperature range of 60 K to 300 K using an electrica l third harmonic technique. In contrast to the previously reported results of Sichel and Pankove, the thermal conductivity increases with decreasing t emperature below room temperature, reaches a maximum and then decreases wit h further decreases in temperature. The thermal conductivity of the LEO-GaN is higher at all temperatures than the HVPE materials. The higher thermal conductivity is correlated with lower values of the threading dislocation d ensity.