Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 41: Quantum dots and wires: Preparation and characterization

HL 41.5: Talk

Tuesday, March 12, 2013, 12:15–12:30, H15

Whispering gallery modes in zinc-blende AlN microdisks embedded with cubic GaN quantum dots — •Matthias Bürger, Marcel Ruth, Stefan Declair, Cedrik Meier, Jens Förstner, and Donat Josef As — Universität Paderborn, 33098 Paderborn, Deutschland

Optical microcavities, like semiconductor microdisks offer applications in quantum information technology as well as low threshold lasing devices. Microdisks support strong confined whispering gallery modes (WGM). In the case of group III-nitrides only microdisks of wurtzite AlN/InN/GaN have been fabricated up to now. However, piezoelectric and spontaneous polarization fields in the polar (0001) c-direction of hexagonal GaN induce a Quantum Confined Stark Effect. These built-in electric fields influence the behavior of optoelectronic devices containing quantum dots (QDs). The recombination probability of electrons and holes is reduced due to a spatial separation of electron and hole wave functions and limits the performance of photonic devices. Therefore, the fabrication of real non-polar metastable cubic GaN (c-GaN) and AlN (c-AlN) in (001) growth direction is very interesting for future applications. To improve the light extraction efficiency QDs can be integrated into microdisks. This work reports on the growth of c-AlN layers and c-GaN QDs on 3C-SiC substrate by means of molecular beam epitaxy. The freestanding microdisk located on a 3C-SiC pedestal were fabricated by reactive ion etching. Morphological investigations were realized by scanning electron microscopy. WGMs were observed in low temperature micro-photoluminescence measurements.