Dissertation
A study of the crystal growth of select II-VI oxides by Czochralski and Bridgman techniques
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2006
DOI:
https://doi.org/10.7273/000006233
Abstract
The crystal growth of ZnO-TeO2 system was experimented by Czochralski and Bridgman techniques. The series of many runs and experimentations helped optimize the growth process, which was faced by a lot of difficulties. These difficulties include, but are not limited to, the evaporation of TeO2 material above 700 ºC, the formation of more than one phase during the growth, and the lack of a ZnO-TeO2 single crystal to start the growth. It was concluded that the main and most persisting problem is that there is no stable phase, in the system that forms a line component at which the crystal growth should be attempted. However, Zn2Te3O8 and ZnTeO3 single crystals were grown using Czochralski and Bridgman techniques, respectively. It was possible to study some of their important optical and electrical properties for the first time. The phase diagram of this system was investigated using powder x-ray diffraction and scanning electron microprobe. CrystalDiffract 1.3 for Windows software was used to simulate x-ray patterns to find the percentages of the resulting phases. It was found that the type of forming phases might be affected by the process, whether if it was calcining, melting, or pulling. Moreover, the history of the material plays an important role in determining what phases form. The glass form of ZnO-TeO2 system was studied as well for this research. One important finding is that the cut-off band edge of this glass depends greatly on the thickness of the sample used. Dielectric constants and resistivities of several glasses were determined. Bridgman technique was used to grow CdTe2O5 single crystals. These crystals are transparent to visible light, and have a mica-like structure. Optical and electrical properties of these crystals, like the dielectric constant and resistivity, of these crystals, were investigated.
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Details
- Title
- A study of the crystal growth of select II-VI oxides by Czochralski and Bridgman techniques
- Creators
- Jalal Mohammad Nawash
- Contributors
- Kelvin G. Lynn (Chair)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 226
- Identifiers
- 99901080536501842
- Language
- English
- Resource Type
- Dissertation