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- Title
Utilization of Anodized Aluminum Oxide Substrate for the Growth of Microcrystals on Polygonized Spirals.
- Authors
Deulkar, Sundeep H.; Bhosale, C. H.; Huang, Jow-Lay
- Abstract
Anodized Aluminum Oxide (AAO) has been utilized as a substrate for the screw dislocation assisted growth of polygonize spirals (PS) of with diameter of the order of ~230 μm by Chemical Vapour Deposition (CVD) process. Stoichiometric microcrystals nucleated on the terraces and tops of these polygonized spirals. Stress inherent in the polygonized spiral morphology (~ 3.57 GPa) was deciphered from the values of the magnitude of shift in observed 2θ values of Glancing Incidence angle XRD (GIXRD) peaks from the standard values (JCPDS 36-1451) for hexagonal Zincite. The growth mechanism of these PS was explained albeit to a limited extent on the basis of the Burton, Cabrera and Frank (BCF) theory and its later modification, wherein data obtained from exsitu SEM measurements concomitant with numerical analysis was utilized to decipher values of the critical radius and supersaturation ratios. Nucleation of microcrystals on the PS was explained on the basis of the supersaturation ratio and the plausible values of diffusion lengths, existent on the summits of these PS. Retardation of the step rotation of the PS, due to elastic stress around the dislocation source and the Gibbs-Thomson effect, was explained on the basis of numerical coefficient ω0, the dimensionless frequency of spiral rotation. Role of stress in inhibition of nucleation on PS of smaller heights and with larger supersaturation ratio, has been discussed albeit qualitatively. The optical characteristics of a single microcrystal has been analyzed by room temperature CL measurements in the wavelength range 350 nm to 650 nm, revealing a single high intensity peak at 382 nm corresponding to a excitonic bandgap of 3.25 eV.
- Subjects
ALUMINUM oxide; ANODIC oxidation of metals; POLYGONIA; CHEMICAL vapor deposition; X-ray diffraction; NUCLEATION
- Publication
International Journal of Nanoscience, 2015, Vol 14, Issue 3, p-1
- ISSN
0219-581X
- Publication type
Article
- DOI
10.1142/S0219581X15500088