Surface And Interface Phonon Polariton Characteristics Of Wurtzite Zno-Based Semiconductor By Infrared Attenuated Total Reflection Spectroscopy
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Date
2011-09
Authors
Lee, Sai Cheong
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
Studies of surface phonon polariton (SPP) characteristics of wurtzite zinc oxide (ZnO) based semiconductors were reported. Attention was paid on the investigations of the SPP and also the interface phonon polariton (IPP) modes in the ZnO heterostructure systems. For comparison, the SPP mode in the bulk ZnO crystal was also investigated. The early effort started with the derivation of the surface polariton (SP) dispersion relations for wurtzite based multilayer systems. The obtained formulations were applied to investigate the dispersion properties of the SPP and IPP modes in the bulk ZnO crystal, ZnO thin film on 6H-SiC substrate, and ZnO/GaN heterostructure on 6H-SiC substrate. To verify the theoretical results, p-polarized infrared (IR) attenuated total reflection (ATR) measurements were carried out. The results were in good agreement with the theoretical spectra simulated by the standard multilayer optics technique. Through comparison of the experimental data and the SP dispersion curves, the origins of the observed modes were verified.
Throughout these studies, a new formulation of the SP dispersion relation was successfully developed via solving Maxwell’s electromagnetic (EM) equations directly based on algebraic manipulation technique. In general, the number of SP branches strongly depends on the localizations at the interfaces. Meanwhile, the thicknesses of epitaxial layers have an important influence on the dispersion properties of the SPP and IPP modes. Apart from that, it was demonstrated that the frequencies of the leaky modes can be predicted by taking into account the damping of the substrate in the numerical calculations of SP dispersion curves.
Description
Keywords
Surface phonon polariton , of wurtzite zinc oxide