Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1545357 | Physica E: Low-dimensional Systems and Nanostructures | 2009 | 5 Pages |
The bandgap of a core–shell CdSe/ZnS quantum dot (QD) is investigated within a temperature range 300–373 K. In this study, the visible absorption and photoluminescence spectra of the QD dispersed in toluene are measured. The obtained results indicate a red shift of 4–6 nm of the peak wavelength associated with a shrinking bandgap of the QD, as the temperature increases from 300 to 373 K. Varshni's law commonly used to describe the bandgap of bulk semiconductors is found also applicable to the QD materials mentioned. Varshni's coefficients are determined as α=(2.0±0.2)×10−4 eV/K, and β=200±30 K, for the temperature range 300–373 K. This shows a smaller α but a similar β value in comparison with the bulk semiconductors, suggesting a better thermal stability of the QD.