Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 74: Quantum dots: Optical properties
HL 74.4: Vortrag
Donnerstag, 14. März 2013, 10:15–10:30, H16
MOVPE grown InAs quantum dots with strain reducing layer — •Matthias Paul, Jan Kettler, Michael Jetter, and Peter Michler — IHFG, Universität Stuttgart, Deutschland
In recent years, InAs semiconductor quantum dots (QDs) have been studied extensively due to their potential application in quantum information networks. Based on their good optical properties and small area densities InAs QDs are excellent candidates for sources of entangled or indistinguishable photons. An implementation in fiber-coupled networks, however, requires emission wavelengths of 1310 nm or 1550 nm to minimize absorption losses.
Therefore, typical emission energies of InAs QDs need to be red-shifted, e.g. by a strain reducing InGaAs layer on top of the QDs. This leads to both a reduction of the effective band gap and to an increase of the size of the QDs which results in lower emission energies.
The fabrication of InAs QDs for the aforementioned spectral range by metal-organic vapor-phase epitaxy usually leads to high area densities. In this case, a structuring a posteriori is necessary to investigate single QDs. By choosing the presented sample structure and growth parameters our samples show area densities of around 106 cm−2. This renders an additional patterning unnecessary. The emission wavelengths of the QDs are around 1050 nm. Distributed Bragg reflectors (DBR), optimized for this spectral range, are used to increase the collection efficiency for micro-photoluminescence measurements. Correlation experiments and time-resolved measurements show the good optical properties of our InAs QDs.