Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 34: Joint Session: Solid State Photon Sources

HL 34.5: Talk

Tuesday, March 15, 2011, 11:45–12:00, HSZ 02

Quantum-Dot Pyramidal Microcavities as Candidates for Electrically Pumped Efficient Single-Photon Sources — •Daniel Rülke, Christoph Reinheimer, Florian Stockmar, Daniel M. Schaadt, Heinz Kalt, and Michael Hetterich — Institut für Angewandte Physik and DFG Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe (Germany)

We have investigated InAs-QDs embedded in reversed pyramidal GaAs microcavities in order to fabricate optically and electrically pumped single-photon sources. As a great advantage of the pyramidal shape the total number of QDs inside the cavity can be controlled by the position of the QD layer during molecular-beam epitaxial growth. Thus, by placing the QD layer close to the tip of the reversed pyramid, a very low number of QDs in the cavity can be achieved, while the facets act as a retroreflector for the emitted light. The pyramidal cavities were fabricated by a a combination of e-beam lithography and a selective wet-chemical etching process. In order to pump QDs electrically they have been embedded in the intrinsic layer of a pin-junction and individual cavities have been connected via bridges to a larger contact pad. To this end, a second non-critical e-beam alignment step had to be added after the wet-chemical etching process before metalisation and a subsequent lift-off process.