Optical and dielectric properties of ZnO tetrapod structures at terahertz frequencies

The low-frequency optical and dielectric properties of ZnO tetrapod structures prepared by thermophysical method were studied by terahertz time-domain spectroscopy. The power absorption, refractive index, and the complex dielectric function were measured in the frequency range from 0.2 to 3.5 THz. Based on a simple effective medium theory, the low-frequency dielectric properties of ZnO tetrapods were found to be associated with the transverse optical E-1 phonon mode, which is consistent with that observed in bulk single-crystal ZnO. (c) 2006 American Institute of Physics.