News Column

Reports from Technical University Describe Recent Advances in Quantum Dots

June 24, 2014

By a News Reporter-Staff News Editor at Physics Week -- Investigators discuss new findings in Quantum Dots. According to news reporting originating in Berlin, Germany, by VerticalNews journalists, research stated, "We present a study about the origin of the huge emission linewidths broadening commonly observed for wurtzite GaN/AlN quantum dots. Our analysis is based on a statistically significant number of quantum dot spectra measured by an automatized mu-photoluminescence mapping system applying image recognition techniques."

The news reporters obtained a quote from the research from Technical University, "A clear decrease of the single quantum dot emission linewidths is observed with rising overall exciton emission energy. 8-band k p based model calculations predict a corresponding decrease of the built -in exciton dipole moments with increasing emission energy in agreement with the measured behavior for the emission linewidths. Based on this proportionality we explain the particular susceptibility of nitride quantum dots to spectral diffusion causing the linewidth broadening via the linear quantum-confined Stark effect. This is the first statistical analysis of emission linewidths that identifies the giant excitonic dipole moments as their origin and estimates the native defect-induced electric field strength to approximate to 2 MV/m."

According to the news reporters, the research concluded: "Our observation is in contrast to less-polar quantum dot systems as e.g. arsenides that exhibit a naturally lower vulnerability to emission linewidth broadening due to almost negligible exciton dipole moments."

For more information on this research see: Spectral diffusion in nitride quantum dots: Emission energy dependent linewidths broadening via giant built-in dipole moments. Physica Status Solidi-Rapid Research Letters, 2014;8(5):408-413. Physica Status Solidi-Rapid Research Letters can be contacted at: Wiley-V C H Verlag Gmbh, Boschstrasse 12, D-69469 Weinheim, Germany.

Our news correspondents report that additional information may be obtained by contacting C. Kindel, Technical University of Berlin, Inst Festkorperphys, D-10623 Berlin, Germany. Additional authors for this research include G. Callsen, S. Kako, T. Kawano, H. Oishi, G. Honig, A. Schliwa, A. Hoffmann and Y. Arakawa.

Keywords for this news article include: Berlin, Europe, Germany, Quantum Dots, Nanotechnology, Quantum Physics, Emerging Technologies

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Source: Physics Week

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