Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 78: Quantum dots: Preparation and characterization

HL 78.8: Talk

Wednesday, April 2, 2014, 18:15–18:30, POT 251

GaN quantum dots grown on AlN by MOVPE — •Farsane Tabataba-Vakili, Konrad Bellmann, Tim Wernicke, Stefan Kalinowski, André Strittmatter, and Michael Kneissl — Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany

GaN quantum dots (QDs) embedded in an AlN matrix enable single and entangled photon emitters operating at room temperature, which are key elements in quantum information science. Stranski-Krastanow (SK) growth of GaN QDs by metal organic vapor phase epitaxy (MOVPE) is subject to a multi-dimensional parameter space of which we have studied the effects of temperature, V/III ratio, and growth interruption (GRI). Desorption effects have a large impact on surface morphologies. Performing a GRI without ammonia supply transforms two dimensional GaN grown under a high V/III ratio into three dimensional islands with a few nm in height and 50-90 nm in diameter. Narrow emission lines of 10 meV from individual islands are observed in µ-PL experiments. Experiments with different V/III ratios during GaN deposition show that a SK-growth mode transition can be achieved for low V/III ratios during GaN deposition. Thereby, QDs with an average height of 4.5 nm and 26 nm in diameter are obtained at densities of 10¹⁰ cm⁻².