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Document Type:Latin Dissertation
Language of Document:English
Record Number:53321
Doc. No:TL23275
Call number:‭3305621‬
Main Entry:Jalal Mohammad Nawash
Title & Author:A study on the crystal growth of select II-VI oxides by Czochralski and Bridgman techniquesJalal Mohammad Nawash
College:Washington State University
Date:2006
Degree:Ph.D.
student score:2006
Page No:226
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 TeO 2 material above 700 °C, 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, Zn 2Te3O8 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.
Subject:Applied sciences; Bridgman growth; CdTe2O5 Bridgman growth; Crystal growth; Czochralski growth; X-ray diffraction of ZnO-TeO2 phases; Zinc oxide-tellurium dioxide glass; Zn2Te3O8 CZ growth; ZnO-TeO2 phase diagram; ZnTeO3 Bridgman growth; Materials science; 0794:Materials science
Added Entry:K. G. Lynn
Added Entry:Washington State University