The authors experimentally find that the thermal conductivity of gallium nitride depends critically on dislocation density using the 3-omega technique. For GaN with dislocation densities lower than 10(6) cm(-2), the thermal conductivity is independent with dislocation density. The thermal conductivity decreases with a logarithmic dependence for material with dislocation densities in the range of 10(7)-10(10) cm(-2). These results are in agreement with theoretical predictions. This study indicates that the hydride vapor phase epitaxy method offers an attractive route for the formation of semi-insulating gallium nitride with optimal thermal conductivity values around 230 W/m K and very low dislocation density near 5x10(4) cm(-2). (c) 2006 American Institute of Physics.
Accurate dependence of gallium nitride thermal conductivity on dislocation density