Interaction of Quatum Dot Placed in the Gap of Nanoparticle Dimers

Marija Gasparic Department of Physics, University of Graz, Graz, Austria Andreas Hohenau Department of Physics, University of Graz, Graz, Austria Ulrich Hohenester Department of Physics, University of Graz, Graz, Austria Joachim R. Krenn Department of Physics, University of Graz, Graz, Austria

Coupling single photon emitters to plasmonic nanostructures yields an attractive platform for the detailed study of strong light-matter interaction. In our work we aim at the lithographically controlled combination of (single) colloidal quantum dots and silver nanoparticles. Therefore, first, we tailor triangle dimers in a bow-tie geometry by electron beam lithography. In a second lithography step we fabricate a polymer mask for quantum dot deposition in the bow-tie gap. On one hand, this configuration places the quantum dot in a plasmonic hotspot due to the (polarization dependent) high field enhancement in the bow-tie gap. Besides the triangle geometry the size of this gap offers an additional lever to tune the optical response of the system (figure). On the other hand, we are contacting the quantum dots we electrically with the silver particles which are in turn connected to electrodes, turning the system into a photoconductive device. Ultimately, we aim at investigating the feasibility and performance of a single-quantum-dot photodetector.

Figure. Measured (left) and simulated (right) extinction spectra of silver triangle dimers with side lengths 80-70-70 nm, 40 nm height and gap dimensions as indicated. The polarization direction is given by the double arrow in the inset.

marija.gasparic@uni-graz.at









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