Friederich Limbach, Christian Hauswald, Jonas Lähnemann, Martin Wölz, Oliver Brandt, Achim Trampert, Michael Hanke, Uwe Jahn, Raffaella Calarco, Lutz Geelhaar, Henning Riechert
Light emitting diodes (LEDs) were fabricated using ensembles of free-standing (In,Ga)N/GaN nanowires (NWs) grown on Si substrates in the self-induced growth mode by molecular beam epitaxy. Electron beam induced current analysis, cathodoluminescence as well as biased $\mu$-photoluminescence spectroscopy, transmission electron microscopy, and electrical measurements indicate that the electroluminescence of such LEDs is governed by the differences in the individual current densities of the single-NW LEDs operated in parallel, i.e. by the inhomogeneity of the current path in the ensemble LED. In addition, the optoelectronic characterization leads to the conclusion that these NWs exhibit N-polarity and that the (In,Ga)N quantum well states in the NWs are subject to a non-vanishing quantum confined Stark effect.
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http://arxiv.org/abs/1210.7144
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