Quickest ever single-step mechanosynthesis of Cd{sub 0.5}Zn{sub 0.5}S quantum dots: Nanostructure and optical characterizations
- Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)
Highlights: Black-Right-Pointing-Pointer Cd{sub 0.5}Zn{sub 0.5}S QDs prepared in 30 min by ball-milling elemental Cd, Zn and S powders. Black-Right-Pointing-Pointer Microstructure characterization is made by XRD employing Rietveld method and HRTEM. Black-Right-Pointing-Pointer Stacking faults in QDs are ascertained both from Rietveld analysis and HRTEM images. Black-Right-Pointing-Pointer Presence of both cubic and hexagonal phases is confirmed by XRD and HRTEM. Black-Right-Pointing-Pointer Quantum confinement is ascertained by blue-shift and optical band gap increment. -- Abstract: Multiphase Cd{sub 0.5}Zn{sub 0.5}S quantum dots (QDs) are prepared for the first time in a record minimum time of 30 min by mechanical alloying the stoichiometric mixture of elemental Cd, Zn and S powders at room temperature under Ar. Initially, the hexagonal phase is formed as major one and then gradually transforms to the cubic phase which is formed coherently on the hexagonal lattice with (0 0 2){sub hexagonal}||(1 1 1){sub cubic} mechanism. In the course of milling up to 15 h, the molar ratio of cubic to hexagonal phase becomes {approx}0.7:0.3. Both high resolution transmission electron microscopy (HRTEM) and X-ray microstructure analyses reveal that these QDs are isotropic in nature, their size reduces to {approx}5 nm after 15 h of milling with a very narrow size distribution and they contain a significant amount of stacking and twin faults. These QDs show very distinct quantum confinement effect and their optical band gaps are higher than that of the bulk CdZnS.
- OSTI ID:
- 22212500
- Journal Information:
- Materials Research Bulletin, Vol. 47, Issue 4; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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