Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Quantum dots and wires: Optical properties II

HL 25.2: Vortrag

Dienstag, 27. März 2007, 14:15–14:30, H17

Optical properties of single InGaN quantum dots — •Sandra Herlufsen, Kathrin Sebald, Henning Lohmeyer, Jürgen Gutowski, Tomohiro Yamaguchi, and Detlef Hommel — Institute of Solid State Physics, University of Bremen, Germany

InGaN quantum dots (QDs) are a promising material for laser structures in the blue to UV spectral region. Before the development of such devices, it is necessary to fully understand the optical properties of the QDs. We will present micro-photoluminescence (μ-PL) measurements on single InGaN QDs grown by metal-organic vapor phase epitaxy. Access to their optical properties can be obtained through the investigations of mesa structures prepared by focused-ion-beam etching. Results achieved by μ-PL measurements will be reported in dependence on the excitation density. The observation of antibinding multiexciton complexes as well as indications for recombination processes from excited states of these complexes will be discussed. The assignment of different emission lines to the same QD was possible on the base of the investigation of the spectral diffusion which occurs due to temporal trapping of carriers in the vicinity of the QD. Temperature dependent μ-PL measurements give indications for the localisation depth of the QDs. Furthermore, the polarisation characteristics of single-QD emission was investigated in order to gain information about the shape and the orientation of the QDs in the sample.