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HL: Fachverband Halbleiterphysik
HL 64: Poster II
HL 64.45: Poster
Donnerstag, 19. März 2020, 10:00–13:00, P1A
Carbon nanodots: Luminescence properties tuned by microcavity devices — •Lukas Trefflich1, Nicole Weizenmann2, Frank Dissinger3, Gabriele Benndorf1, Chris Sturm1, Rüdiger Schmidt-Grund1,4, Siegfried R. Waldvogel3, Ralf Seidel2, and Marius Grundmann1 — 1Felix Bloch Institute for Solid State Physics, Universität Leipzig — 2Peter Debye Institute for Soft Matter Physics, Universität Leipzig — 3Institute for Organic Chemistry, Johannes Gutenberg Universität Mainz — 4now at: Institute of Physics, Technische Universität Ilmenau
The carbon nanodots (cdots) made from citric acid and a stabilizing amine component emit bright light in the spectral range between 390 nm and 600 nm. To investigate their size-dependent luminescence properties, we separate them with gel-electrophoresis and perform time- and energy-resolved photoluminescence (PL). We propose a streched exponential law [1] for the emission decay. The mean luminescence lifetime depends on the emission wavelength (cf. [2]) and the particle size. We obtain lifetimes in the range of 0.6 ns to 2 ns. The emission of the cdots can be enhanced by incorporating them in a planar microcavity. That allows to tune the emission wavelength of the device by varying the optical thickness of the cavity layer. We produce such a device with pulsed laser deposition and characterize it with power dependent PL. The power-dependence fits to a multimode laser-model [3], indicating lasing, with a threshold intensity of 32 MW cm−2. [1] Milovanov et al., Phys. Rev. B, 2007, 76 [2] Kahn and Kim, Sci. Rep., 2019, 9 [3] Casperson, J. Appl. Phys., 1975, 46