title: Blinking statistics of silicon quantum dots.
abstract: 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.
authors: Materials Physics, School of ICT, Royal Institute of Technology, Electrum 229, SE-16440 Kista-Stockholm, Sweden. bbruhn@kth.se
authors: Benjamin
authors: B
authors: Bruhn
authors: Jan
authors: J
authors: Valenta
authors: Fatemeh
authors: F
authors: Sangghaleh
authors: Jan
authors: J
authors: Linnros
mesh_terms: D049449:Luminescence; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D010084:Oxidation-Reduction; D045663:Quantum Dots; D012825:Silicon / Q000737:chemistry*
chemical_list: D012825:Silicon