Authors: Ivana Lj Validžić Miodrag Mitrić S Phillip Ahrenkiel Mirjana I Čomor
Publish Date: 2015/05/19
Volume: 46, Issue: 8, Pages: 3679-3686
Abstract
We report the synthesis of zinc oxide ZnO nanoleaves and nanorods under high and extremely high alkaline experimental conditions via a simple and lowtemperature method By performing transmission electron microscopy it is found that the nanoleaves and nanorods grow along the 001 direction Anisotropic ie hkldependent lineshape broadening is observed in ZnO powder diffraction patterns Rietveld analysis using Fullprof with model for handling the anisotropic sizelike broadening is performed on these diffraction patterns The refinement showed that ZnO powders belong to the hexagonal ZnS structure type with space group P63mc and confirmed that the nanoleaves and nanorods are oriented along the 001 direction Results of visualization in 3D of the average crystallite shape obtained from refinement of spherical harmonics coefficients showed elongated shapes in the both samples exhibiting a slight twisting for nanoleaves Diffuse reflectance measurements reveal that the optical bandgap energies found for the ZnO nanoleaves and nanorods is somewhat smaller than a widedirect band gap of 337 eV We argued that well defined and strong photoluminescence PL bands in the visible part that belong to the defects may influence the observed displacement of a ultraviolet UV nearbandedge emission and which is related with obtained slightly lower bandgap energies than the established band gap of bulk ZnO We discuss processes behind the multicolor UV/violet/blue/green/yellow emission band in PL spectra
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