Roles of Dislocation Density to the Scattering of Nano-acoustic Waves in GaN

Tzu-Ming Liu；Shih-Ze Sun；Chieh-Feng Chang；Guan-Ting Chen；Chang-Chi Pan；Jen-Inn Chyi；Chi-Kuang Sun

Chinese Journal of Physics

49卷1期（2011 / 02 / 01）

171 - 175

英文

We have investigated how the density of threading dislocations in GaN affects the decay of the intensity of nano-acoustic waves. We carried out measurements using a reflection-type femtosecond pump probe, and thus, we determined the local dislocation density from the lifetime of nano-acoustic waves. We found that for a dislocation density of 10^8 cm^(-2), defect scattering will surmount other scattering mechanisms and dominate the attenuation of 100GHz acoustic phonons.