Electromechanical coupling coefficient of semiconducting hexagonal crystal measured by Brillouin scattering

Super high frequency (SHF) acoustic measurement realizes the piezoelectric characterization in semiconducting material without the effect of electrical conducting. We have proposed the method for measuring shear and extensional electromechanical coupling coefficient k
15
and k
33
in a semiconducting crystal simultaneously, using Brillouin scattering method. In ZnO crystal, k
15
value measured from measured acoustic velocities was in good accordance with the previously reported constant. We also have found large variety in effective piezoelectricity, implying variety of resistivity in the ZnO crystal.