The Influence of Dopants on the Nucleation of Semiconductor Nanocrystals from Homogeneous Solution
Authors: Bryan, J. Daniel; Schwartz, Dana A.; Gamelin, Daniel R.
Source: Journal of Nanoscience and Nanotechnology, Volume 5, Number 9, September 2005 , pp. 1472-1479(8)
Publisher: American Scientific Publishers
Abstract:The influence of Co2+ ions on the homogeneous nucleation of ZnO is examined. Using electronic absorption spectroscopy as a dopant-specific in-situ spectroscopic probe, Co2+ ions are found to be quantitatively excluded from the ZnO critical nuclei but incorporated nearly statistically in the subsequent growth layers, resulting in crystallites with pure ZnO cores and Zn1-xCoxO shells. Strong inhibition of ZnO nucleation by Co2+ ions is also observed. These results are explained using the classical nucleation model. Statistical analysis of nucleation inhibition data allows estimation of the critical nucleus size as 25±4 Zn2+ ions. Bulk calorimetric data allow the activation barrier for ZnO nucleation containing a single Co2+ impurity to be estimated as 5.75 kcal/mol cluster greater than that of pure ZnO, corresponding to a 1.5 × 104-fold reduction in the ZnO nucleation rate constant upon introduction of a single Co2+ impurity. These data and analysis offer a rare view into the role of composition in homogeneous nucleation processes, and specifically address recent experiments targeting formation of semiconductor quantum dots containing single magnetic impurity ions at their precise centers.
Document Type: Research article
Publication date: 2005-09-01
- Journal for Nanoscience and Nanotechnology (JNN) is an international and multidisciplinary peer-reviewed journal with a wide-ranging coverage, consolidating research activities in all areas of nanoscience and nanotechnology into a single and unique reference source. JNN is the first cross-disciplinary journal to publish original full research articles, rapid communications of important new scientific and technological findings, timely state-of-the-art reviews with author's photo and short biography, and current research news encompassing the fundamental and applied research in all disciplines of science, engineering and medicine.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Terms & Conditions
- ingentaconnect is not responsible for the content or availability of external websites