Increased thermal conductivity of free-standing low-dislocation-density GaN films

Proposed hihg-power electronic and optoelectronic applications of GaN materials rely heavily on the effectiveness of heat removal from the devices. Here we report the results of our measurements of theraml conductivity in the thick free-standing GaN films prepared by hybride vapor phase epitaxy. The fabrication method allows one to grow the low-dislocation density films without the use of non-native substrates. Our experimental data show that the room temperature theraml conductivity in free-standing GaN films can be as high at 225 W/mK, which is a factor for the given sample parameters, indicates that the low-temperature thraml conductivity can reach a record value of 7460 W/mK. The presented results are important for the thermal management optimization of GaN-based devices.