Blinking Statistics of Silicon Quantum Dots
2011 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 11, no 12, 5574-5580 p.Article in journal (Refereed) Published
The blinking statistics of numerous single silicon quantum dots fabricated by electron-beam lithography, plasma etching, and oxidation have been analyzed. Purely exponential on- and off-time distributions were found consistent with the absence of statistical aging. This is in contrast to blinking reports in the literature where power-law distributions prevail as well as observations of statistical aging in nanocrystal ensembles. A linear increase of the switching frequency with excitation power density indicates a domination of single-photon absorption processes, possibly through a direct transfer of charges to trap states without the need for a bimolecular Auger mechanism. Photoluminescence saturation with increasing excitation is not observed; however, there is a threshold in excitation (coinciding with a mean occupation of one exciton per nanocrystal) where a change from linear to square-root increase occurs. Finally, the statistics of blinking of single quantum dots in terms of average on-time, blinking frequency and blinking amplitude reveal large variations (several orders) without any significant correlation demonstrating the individual microscopic character of each quantum dot.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2011. Vol. 11, no 12, 5574-5580 p.
Blinking, intermittency, silicon, quantum dot, nanocrystal, photoluminescence, statistical aging, bleaching
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-58819DOI: 10.1021/nl203618hISI: 000297950200081ScopusID: 2-s2.0-83655164324OAI: oai:DiVA.org:kth-58819DiVA: diva2:474197
QC 201201092012-03-212012-01-092015-10-01Bibliographically approved