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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties

HL 91.11: Poster

Donnerstag, 14. März 2013, 16:00–20:00, Poster A

Study of excitonic states in single InAs quantum dots by low-temperature SNOM — •Alexander Senichev¹, Vadim Talalaev^1,2, Jörg Schilling², George Cirlin^3,4,5, and Peter Werner¹ — ¹Max-Planck-Institut, Halle, Germany — ²Martin-Luther-Universität, ZIK "SiLi-nano", Halle, Germany — ³A. F. Ioffe Physico-Technical Institute, St. Petersburg, Russia — ⁴St. Petersburg Physics and Technology Center for Research and Education, St. Petersburg, Russia — ⁵Institute for Analytical Instrumentation, St. Petersburg, Russia

We report on near-field optical spectroscopy on InAs quantum dots embedded in a GaAs matrix. Quantum dot samples are grown by molecular beam epitaxy in different configuration of the active region. Sharp spectral lines corresponding to optical recombination in single quantum dots are selected. The spectral width of most resonances is quite narrow and comparable with the resolution of our monochromator (0.1 meV). Varying the excitation power density from 2W/cm2 to 300W/cm2 power dependence of photoluminescence (PL) parameters is investigated. For spatial PL imaging (spatial resolution 300 nm), the fiber probe is scanned across the sample surface, and a full PL spectrum is recorded at every pixel. The intensity of the observed emission lines shows approximately linear power dependence and saturate at the power of 100W/cm2. The results are discussed in respect to the capability of SNOM and provide a better understanding of the exciton behavior of individual QDs.