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You searched for +publisher:"NSYSU" +contributor:("Lau-Wei Chang"). Showing records 1 – 2 of 2 total matches.

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NSYSU

1. Chang, Chi-wei. Growth of (0002)ZnO films on nitridated (001) LiGaO2 substrate by chemical vapor deposition.

Degree: Master, Materials and Optoelectronic Science, 2013, NSYSU

In this thesis, the growth of c-plane zinc oxide (ZnO) epitaxial films on nitridated c-LiGaO2 substrates by a homemade thermal chemical vapor deposition. Use Zinc Acetylacetonate was used as zinc precursor. High purity oxygen and nitrogen are used as reaction gas and carrier gas, respectively. We control the quality of films by optimizing the parameters of growth temperature, growth pressure and oxygen partial pressure. The properties of the ZnO films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), photoluminescence spectra (PL), Raman spectra (Raman) and transmission electron microscopy(TEM). The results show that the crystal quality and surface morphologyies of c-plane ZnO films are strongly related to the growth temperature, growth pressure and oxygen partial pressure. When growth temperature is 575â, the ZnO XRD signal is the strongest and hexagonal shapes of the zinc oxide grains are obvious and with direction. The results of changing growth pressure showed that when the pressure is 300torr, the film is the smoothest. The XRD results show that the FWHM decreases with the growth pressure increase. This phenomenon caused improvement of crystal quality, and FWHM values reach a minimum at 0.13°, 300torr. Finally, in a fixed total oxygen and nitrogen mixed gas flow rate (1000sccm), we changed the flow rate of oxygen reactive gas, The results showed that when the ratio of nitrogen and oxygen were changed from 1:3 to 3:1, the XRD signals are obvious strong and all of the FWHM are less than 0.2 °. The SEM images show flat with continuous film morphologies, while the partial pressure of oxygen are further increase or decrease, the XRD signals drop, and the FWHM values increase, the SEM images show distributed granular, with obvious grain boundary morphologies. To further analysis of ZnO epitaxial films, the epitaxied orientation relationship was studied by TEM selected area electron diffraction analysis. The shift of XRD diffraction peaks and Raman spectra characteristic peak of E2 demonstrated the occurrence of interned stress during the epitaxial growt. Photoluminescence spectra results can infer the yellow-green emission was caused by defect, not by the cerium doped substrate. Advisors/Committee Members: Jih-Jen Wu (chair), Lau-Wei Chang (chair), Der-shin Gan (chair), Mitch, Ming-Chi Chou (committee member).

Subjects/Keywords: CVD; nitridation; LGO; epitaxy; ZnO

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chang, C. (2013). Growth of (0002)ZnO films on nitridated (001) LiGaO2 substrate by chemical vapor deposition. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0706113-183724

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Chang, Chi-wei. “Growth of (0002)ZnO films on nitridated (001) LiGaO2 substrate by chemical vapor deposition.” 2013. Thesis, NSYSU. Accessed November 17, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0706113-183724.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Chang, Chi-wei. “Growth of (0002)ZnO films on nitridated (001) LiGaO2 substrate by chemical vapor deposition.” 2013. Web. 17 Nov 2019.

Vancouver:

Chang C. Growth of (0002)ZnO films on nitridated (001) LiGaO2 substrate by chemical vapor deposition. [Internet] [Thesis]. NSYSU; 2013. [cited 2019 Nov 17]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0706113-183724.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Chang C. Growth of (0002)ZnO films on nitridated (001) LiGaO2 substrate by chemical vapor deposition. [Thesis]. NSYSU; 2013. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0706113-183724

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


NSYSU

2. Yu, Chung-Yi. Mechanical properties of ultrafine grained aluminum.

Degree: PhD, Materials Science and Engineering, 2003, NSYSU

It has been shown that alloys with submicron-grained structure can be produced by severe plastic deformation (SPD). However, our understanding about the characteristics of mechanical behaviors of these materials is still limited. According to the literature, many alloys exhibit quite different mechanical properties as the grain size decreasing to submicrometer range. In this study, commercial purity aluminum (AA1050) of grain size ranging from 0.35 to ~ 45 mm was obtained by the proper combination of equal-channel angular extrusion (ECAE) and annealing treatment. The influences of grain size, testing temperature and boundary character on the mechanical properties were studied in this work. Generally speaking, the materials of grain sizes below 1mm have quite different mechanical properties than those of coarser grain sizes. In tensile tests, they exhibited yield drop immediately followed by work softening at RT, while they showed Lüders extension followed by work hardening at 77K. In addition, their yield strength at RT was about 20% higher in compression than in tension. The submicron-grained aluminum has much higher strength but lower tensile ductility than large grained aluminum at room temperature, while it exhibits both high strength and good ductility at 77K. This finding suggests that the poor tensile ductility of submicron-grained alloys at room temperature may be improved by reducing the dynamic recovery rate. The Hall-Petch slope in the submicrometer grain size range showed positive deviation from that extended from coarser grains at both room temperature and 77K. This might be arisen from the phenomenon of inhomogeneous yielding as grain size below 1 mm. In addition, the grain boundary character distribution was found to have influence on the tensile properties of matrials of submicrometer grain sizes. As the grain size increases to the range between 1 mm and 4 mm, the tensile deformation at RT proceeds by the propagation of Lüders band initially, and followed by strain hardening. For materials of grain sizes greater than 4 mm, a normal strain hardening behavior of coarse-grained aluminum resumes. Advisors/Committee Members: Chih Pu Chang (chair), Chih-Ching Huang (chair), Li-Hui Chen (chair), Po-We Kao (committee member), Lau-Wei Chang (chair), Der shin Gan (chair).

Subjects/Keywords: Aluminum; ECAE; Mechanical properties; Ultrafine grain; Boundary character; Deformation structure

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Yu, C. (2003). Mechanical properties of ultrafine grained aluminum. (Doctoral Dissertation). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0705103-154538

Chicago Manual of Style (16th Edition):

Yu, Chung-Yi. “Mechanical properties of ultrafine grained aluminum.” 2003. Doctoral Dissertation, NSYSU. Accessed November 17, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0705103-154538.

MLA Handbook (7th Edition):

Yu, Chung-Yi. “Mechanical properties of ultrafine grained aluminum.” 2003. Web. 17 Nov 2019.

Vancouver:

Yu C. Mechanical properties of ultrafine grained aluminum. [Internet] [Doctoral dissertation]. NSYSU; 2003. [cited 2019 Nov 17]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0705103-154538.

Council of Science Editors:

Yu C. Mechanical properties of ultrafine grained aluminum. [Doctoral Dissertation]. NSYSU; 2003. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0705103-154538

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