Title page for etd-0812114-122025


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URN etd-0812114-122025
Author Han-hsiang Ko
Author's Email Address No Public.
Statistics This thesis had been viewed 5385 times. Download 408 times.
Department Physics
Year 2013
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Structural and optical properties of nonpolar a-ZnO grown by Rf-sputtering
Date of Defense 2014-07-24
Page Count 55
Keyword
  • photoluminescence
  • ZnO
  • oxygen content
  • rf sputtering
  • nonpolar
  • a-plane
  • Abstract This thesis focuses on studying the structural and optical properties of nonpolar a-ZnO thin films grown on r-Al2O3 substrates (a-ZnO/r-Al2O3). The crystallographic qualities and orientations of a-ZnO thin films grown by rf-sputtering are analyzed by X-ray diffractometry (XRD) through θ-2θ scan, φ-scan, rocking curve and GIXRD. The morphology and cross section of the thin films grown by different parameters were analyzed by SEM. From PL measurement, we knew the properties of carries.
    The growth of a-ZnO epitaxial thin films was attempted at different substrate temperatures. The epitaxial relations between the thin films and substrates have been determined by the φ-scans to be [0002]ZnO || [¯1 011]Al2O3 and [1¯1 00]ZnO || [1¯2 10]Al2O3. The full width at half maximum (FWHM) of rocking curve for each sample decreases with increasing substrate temperature. From SEM observations, the surface morphology demonstrates elongated granular structures along the c-axis.
    The properties of the a-ZnO thin films depend on the PAr:PO2 ratios and 2.8:1 gives the best results byθ-2θand rocking curve . When the flux of oxygen was increased, the aspect ratio of the elongated grains would decrease. From room-temperature photoluminescence (RT-PL) spectroscopy, the zinc vacancy and oxygen content determine much of the observed material properties of the a-ZnO thin films. According to variable-temperature dependent PL spectroscopy, the energy positions of FX, DAP and VZn peaks do not shift as a result of temperature change, which we contemplate as a 3D to 2D transition of the electronic behaviors as the temperature decreases.
    Advisory Committee
  • Li-Wei Tu - chair
  • Zhi-xiong liao - co-chair
  • Den -Jun Jang - co-chair
  • Quark Chen - advisor
  • Files
  • etd-0812114-122025.pdf
  • Indicate in-campus at 3 year and off-campus access at 3 year.
    Date of Submission 2014-09-12

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