Synchrotron Radiation Technology Study of Semiconductors and Heterostructures
Date Issued
2009
Date
2009
Author(s)
Chen, Yen-Ting
Abstract
During the past decade, synchrotron light sources have become indispensable tools for advanced scientific research. Synchrotron light is used widely in basic and applied research throughout the fields of materials science, biology, medicine, physics, chemistry, chemical engineering, geology, archeology, environmental science, energy, electronics, micro-mechanical engineering, and nanotechnology. For this reason synchrotron light sources have been coined "magic lamps of science". his thesis will focus on synchrotron radiation technology studies of semiconductors and heterostructures. The thesis consists of five chapters: in chapter one, we introduce the synchrotron radiation, including the explanation, history, sources, properties, production and applications of synchrotron radiation. In chapter two, we introduce the experimental instruments and the theoretical background, including photoluminescence (PL), x-ray diffraction (XRD), and x-ray absorption (XAS). In chapter three, we analyze the powder XRD spectrums and the temperature dependent of PL spectrums of the thin film AlGaN and MgZnO samples. n chapter four, we discuss the synchrotron radiation powder XRD. In the beginning of chapter four, we introduce two crystallographic databases, Inorganic Crystal Structure Database (ICSD) and International Centre for Diffraction Data (ICDD) which are usually used by our laboratory members. We illustrate the methods of analyzing the XRD data by General Structure Analysis System (GSAS) program with pictures and measure these XRD data by using the experimental instrument for synchroton radiation X-ray powder diffraction at beamline 01C2 of the National Synchrotron Radiation Research Center (NSRRC). The analyzed XRD data include AlN on sapphire substrate, bulk AlN, Si-Ge-Si, 3C-SiC on sapphire substrate and ZnO on sapphire substrate. Then, we refine the crystal structure of five kind samples above mentioned by GSAS. In this chapter, we encounter a problem: we know that the crystal structure of AlN and ZnO are wurtzite in our all measurement. Nevertheless, the result shows that crystal structural refinement is cubic system. Why? We guess that the crystal structure is transformed because the energy of the incident synchrotron radiation x-ray (28keV) is too high. n chapter five, we discuss the synchrotron radiation XAS. We introduce the applications of II-VI compound materials, CdSeTe, ZnMnTe, and CdZnTe. We measure these samples that include CdSeTe, ZnMnTe, CdZnTe bulk and thin film GaN/Si, ZnO/Si, HfO2/Si by using the Athena and Artemis program. The results show that the various compositions of certain element in the above compound materials cause the small-size atoms substitute the big-size atoms in the crystal lattice, so the bond length and coordination number between atoms are changed. Therefore, we can understand the local structure of the specific elements.
Subjects
Synchrotron Radiation
Semiconductor
Heterostructure
Type
thesis
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