Application of terahertz time-domain ellipsometry to the characterization of c- and m-surface in ZnO

In order to demonstrate the application of terahertz time-domain ellipsometry (THz-TDE) in the characterization of anisotropic semiconductors, we studied two zinc oxide (ZnO) single crystals with different orientations. The optical properties such as the refractive index of ZnO samples are obtained by ellipsometric parameters, while the electrical properties of ZnO samples are well deduced and fitted using the Drude model. These results suggest that THz-TDE can effectively obtain the optical and electrical properties of anisotropic semiconductors and can be used to characterize semiconductors with carrier densities higher than 10¹⁶ cm⁻³.