Effect of O₂ Flow Rate on the Morphological and Optical Properties of ZnO Nanocrystals

Abstract:

The morphological and optical properties of ZnO nanocrystals prepared by thermal evaporation of Zn powders were studied at both upstream and downstream under different O₂ flow rates. The morphological evolution was observed by scanning electron microscopy. With O₂ flow rates changing from 0.25 sccm to 1 sccm, the caps of the ZnO nanonails become bigger and the stems gradually disappear at upstream, and the diameters at the top of ZnO nanorods become thicker and the length become longer at downstream. Room temperature PL study shows that UV emission is relatively enhanced with increasing O₂ flow rates. Computational fluid dynamics simulation was performed, which indicates that the morphological evolution of the ZnO structures results from the competition between the axial growth and the radial growth based on different O₂ and Zn vapor partial pressure.

• Periodical: Advanced Materials Research (Volumes 554-556)
• Pages: 70-75
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.554-556.70
• Online since: July 2012
• Authors: Hui Juan Tian, Jun Bo Xu, Ya Jun Tian, Hao Wen
• Keywords: Chemical Vapor Deposition (CVD), Computational Fluid Dynamics (CFD), Morphological Evolution, ZnO Nanocrystal

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