Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 53: GaN: Devices

HL 53.4: Talk

Wednesday, March 13, 2013, 10:45–11:00, H15

Toward light-emitting diodes based on homogenous III-N nanowire ensembles on Si substrates — •Mattia Musolino, Christian Hauswald, Friederich Limbach, Martin Wölz, Tobias Gotschke, Oliver Brandt, Lutz Geelhaar, and Henning Riechert — Paul-Drude-Institut für Festkörperelektronik, Berlin

Light-emitting diodes (LEDs) based on III-N nanowires (NWs) are an attractive alternative to conventional planar layers, since the NW geometry enables the growth of (In,Ga)N/GaN heterostructures with high crystal quality on cost-effective Si substrates. However, (In,Ga)N/GaN NW ensembles grown by self-assembly processes suffer from multicolour emission. Homogeneous emission can be achieved by controlling the diameter of the NWs by selective-area growth (SAG). LEDs based on such NW ensembles have so far been fabricated only on expensive and not very versatile GaN templates.

Our approach for the SAG of NWs on Si substrates by molecular beam epitaxy exploits the longer incubation time of GaN NWs on the patterned SiOx mask than in openings to an AlN buffer layer. We optimized the growth of the AlN buffer in order to attain a thickness low enough to allow LED operation and at the same time preserve the requirements necessary for SAG. In order to prove the feasibility of operating devices on such an AlN buffer we fabricated functional (In,Ga)N/GaN LEDs based on NWs grown by self-assembly processes on this thin buffer layer. In addition, we demonstrated the SAG of GaN NW on such buffers, thus paving the way towards homogeneous NW LEDs on Si substrates.