| Summary: | 碩士 === 國立臺灣師範大學 === 物理學系 === 100 === In this thesis, we study the optical properties of semiconductor materials, especially on infrared reflectance spectra, the InN films grown on sapphire substrates, different compositions of series of InAs1-xNx films grown on InP substrates and In0.5(Ga1-xAlx)0.5P films grown on GaAs substrates were used in this study.
Infrared spectroscopy is a non-destructive measurement which can get the information from the lattice vibrations of the samples without doing any damage. Fourier transform infrared (FTIR) Bruker IFS 66 V/S were employed to do a series measurements. A dielectric response model was used to determine the optical and transport properties of the semiconductors.
From infrared spectra of InN/sapphire, we found the E1 (TO) phonon mode frequencies were obtained at 473~478 cm−1 by dielectric response function fitting.
From infrared spectra of InAs1-xNx/InP, the InAs-like TO phonon mode increases with the increase of N composition x and the InN-like TO phonon mode also increases with the increase of N composition x. With increasing x, the effective mass and carrier concentration increase greatly but mobility decrease greatly.
From infrared spectra of In0.5(Ga1-xAlx)0.5P/GaAs, there are apparently four main peaks. And we also could define the four TO frequency peak from low frequency to higher frequency are the GaAs phonon mode, InP-, GaP- and AlP-like phonon mode that similar with reference. However, there is a fifth phonon mode that is the Cu-pt type ordered characteristics affect the TO-phonon peak split into two TO mode. And the InP and GaP mode combine into one mode that the effects are made possible by the strong coupling between the Ga-P and In-P vibrations.
In my works, we also have analyzed the high-frequency dielectric constant, carrier concentration, mobility and effective mass and the thickness of the films of these materials. Conductivity had been calculated, too. This study established a data base of these materials and provides a reference for their applications.
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