Study of optical and dielectric properties of annealed ZnO nanoparticles in the terahertz regime
ABSTRACT The frequency-dependent optical and dielectric properties of annealed ZnO nanoparticles in the range of 0.1 to 0.9 THz are
studied by using terahertz time-domain spectroscopy (THz-TDS). The refractive index, power absorption and complex dielectric
constants are obtained and the experimental results are well fit with a simple effective medium theory in conjunction with
a pseudo-harmonic model. This study reveals that annealed ZnO nanoparticles exhibit the similar phonon response characteristics
to the single ZnO crystal and other ZnO nanostructures, such as tetrapods and nanowires.