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Synthesis of ZnO Crystals by Chemical Vapor Transport Method

Author: LiZhenJun
Tutor: WeiZhiRen
School: Hebei University
Course: Optical Engineering
Keywords: ZnO crystal synthesis CVT directional
CLC: O484.1
Type: Master's thesis
Year: 2009
Downloads: 19
Quote: 0
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Abstract


In this paper, different morphologies of zinc oxide (ZnO) crystals were synthesized on alumina (Al2O3) wafer in an open chemical vapor transport system under normal atmosphere. In the experiment, ZnO powder was used for crystal-growing material, NH4Cl was used for transport gas, the growing temperate was 950℃, and reacting time was 1h. Hexangular ZnO crystals directional grown on wafer were prepared by adjusting the flux of transport gas and the proportion of HCl to control the morphology.At 920℃, using NH3 as transport gas only, many fantastic ZnO crystals, such as tubular, claviform, pectinate, flowerlike, leaflike, beltlike and so on, were synthesized. The analysis on the reaction mechanisms concluded that the cause of growing hollow crystals was the existing of Zn drop in reacting system. By adding more HC1 or enhancing temperature, the morphology of crystals could be controlled efficiently. So, hexangular ZnO crystals were prepared on alumina wafer.Using mixed HCl and NH3 as transport gas, when the molar concentrateion of HC1 was higher than NH3, hexangular ZnO crystals were directionally growed on Al2O3 wafer. Higher quality single crystal film was prepared on ZnO homogenous substrate, andω-scan of single crystal diffraction showed the FWHM was 271.8 arcsec. It has been testified the open chemical vapor transport (CVT) system under normal atmosphere can be used for growing achromatous transparency ZnO single crystal.

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Thin Film Physics > Film growth,structure and epitaxy
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