2008/08/23 by M. D. Leistikow, M.D. Leistikow, J. Johansen +5
Engineering · Materials Science · Physics and Astronomy · #Near-Field Optical Microscopy #Photonic Crystals and Applications #Quantum Dots Synthesis And Properties #physics.optics
paper · pdf · doi:10.1103/physrevb.79.045301
published as Phys. Rev. B 79, 045301 (2009)
arxiv created 2008/08/23 · openalex publication_date 2009/01/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We study experimentally time-resolved emission of colloidal CdSe quantum dots in an environment with a controlled local density of states (LDOS). The decay rate is measured versus frequency and as a function of distance to a mirror. We observe a linear relation between the decay rate and the LDOS, allowing us to determine the size-dependent quantum efficiency and oscillator strength. We find that the quantum efficiency decreases with increasing emission energy mostly due to an increase in nonradiative decay. We manage to obtain the oscillator strength of the important class of CdSe quantum dots. The oscillator strength varies weakly with frequency in agreement with behavior of quantum dots in the strong confinement limit. Surprisingly, previously calculated tight-binding results differ by a factor of 5 with the measured absolute values. Results from pseudopotential calculations agree well with the measured radiative rates. Our results are relevant for applications of CdSe quantum dots in spontaneous emission control and cavity quantum electrodynamics.