May 13 2008
Quantums dots are semiconductor nanocrystals with quantum properties that hold promises for a wide range of applications from superfast computing to cancer cures. Quantum dots can be made using a number of synthesis techniques including MBE (Molecular beam epitaxy), RF (Radio Frequency) sputtering and LPE (Liquid Phase Epitaxy) but the most promising path is chemical synthesis.
HRTEM image of CdS (left) and ZnS quantum dots (right)
Recently conducted original research by S.S. Nath, D. Chakdar, G. Gope and D K Avasthi of National Institute of Technology Silchar and IUAC has been published in the open access journal, AZoJono. This paper investigates the fabrication of quantum dots via a chemical method at room temperature. Styrene Butadane Rubber (SBR) latex which acts as matrix, plays the key role in controlling the size and shape of quantum dots during sample fabrication and after synthesis. The samples were characterized by different techniques to reveal their nano nature.
The researchers successfully prepared almost spherical quantum dots of approximately 10 nm diameter. Impedance analysis showed that admittance of CdS quantum dots and ZnS quantum dots changes with changes in frequency while the admittance of bulk CdS and ZnS remains almost constant with changes in frequency. Moreover, impedance analysis demonstrates that CdS quantum dots can act as electronic tuned circuits with an equivalent resonant frequency of 23 MHz. Meanwhile ZnS quantum dots can act as high pass filters with a cut off frequency of 20 MHz.
The article is freely available to view in full at https://www.azonano.com/details.asp?ArticleId=2159.