Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 15: Quantum Dots and Wires: Fabrication and Devices

HL 15.9: Vortrag

Montag, 7. März 2016, 17:30–17:45, H16

Site-Controlled MBE Growth of III/V Semiconductor Nanowires Induced by Focused Ion Beam — •Sven Scholz, Rüdiger Schott, Arne Ludwig, and Andreas D. Wieck — Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum

Nanowires (NWs) are near one-dimensional structures that typically have a huge length-to-width ratio. This is the base of fascinating properties. Heterostructures of highly lattice mismatched materials can be combined without dislocations. Metastable phases, unattainable in bulk materials like wurtzite GaAs or InAs, are feasible. We present focused ion beam (FIB) induced molecular beam epitaxy (MBE) grown NWs from site selectively deposited Au seeds. The possibility of maskless patterning makes FIB a powerful tool and an alternative to conventional lithography based methods in semiconductor processing. By implanting distinct spots of Au ions in arbitrary distributions on GaAs substrates, we initiate GaAs and InAs NW growth in the MBE. We show, that a small amount of ions resulting in small droplets appropriate to catalyse a single NW per site with a yield of above 60%. The small size of the droplets leads to NWs with diameters of 20 nm and below, which results in high aspect ratios. Additionally to the optimization of the morphology, the crystal structure was investigated and improved to achieve defect free and single crystalline NWs. Also the bandgap modulation due to the growth of heterostructures in single NWs will be presented.