Optical and Material Property Studies of ZnO Thin Film
Date Issued
2005
Date
2005
Author(s)
Wang, Jiun-Bi
DOI
en-US
Abstract
In this research, we compare three series samples of Zinc Oxide. For series one, we got three ZnO sample in the same epitaxy structure but with different annealing temperature. And the series two are the ZnO film which grown on different substrate. The last series are p-type and n-type ZnO thin film grown on Al2O3 with different thickness. All series were grown by metalorganic chemical vapor deposition (MOCVD). For series one (with different annealing temperature), the surface morphology was determined by scanning electron microscopy (SEM), it showed that difference of the grain size with different thermal annealing temperature. From XRD data we knew that the crystallinity quality of samples did not monotonously improve with annealing temperature. Using Raman scattering we could observe the annealed samples showed a decrease of the intensity and linewidth of E1 (LO) mode peak with increasing annealing temperature. From PL spectra, two emission bands were observed. One is the ultraviolet (UV) band with peak position at about 380 nm caused by the transition of excitons, and the other was the green band commonly referred to as a deep-level or trap-state emission caused by the defects of the crystal. So we compared the green band of this series samples to determine which one have the best quality that we know in what kind of the condition will get a high quality material. For series two (pair of ZnO grown on Si and sapphire), used the XRD we could find that the lattice constant of materials grown on different substrate. Comparing with the lattice constant and the UV peak shift, we could find the relationship between the stress and the PL peak positions. From Raman scattering spectra, we could find the more exactly relationship between stress and spectrum theoretically, but our XRD experiment results could not fitted the value of theory. Therefore, our research could not find the relation equation about Raman shift and stress. But the Raman shift was still observed. For last series, we were experimented with XRD, reflectance, PL and Raman scattering. The XRD would determine the sample quality and reflectance could find the thickness of film. PL showed the lighting efficiency and intensity of defect, and Raman spectrum represented the symmetry of material. Those experiment results were found the best quality of sample and to find the best fabricated condition of ZnO thin film materials.
Subjects
氧化鋅
熱退火
光激發光譜
拉曼散射
p型及n型
ZnO
annealing temperature
PL
Raman
XRD
Type
thesis
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