Dresden 2006 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Halbleiterphysik

HL 42: Quantum dots and wires: Preparation and characterization I

HL 42.2: Vortrag

Donnerstag, 30. März 2006, 11:15–11:30, POT 51

Axial and radial growth of GaN-nanowires by molecular beam epitaxy — •C. Chèze¹, L. Geelhaar¹, Ph. Komninou², Th. Kehagias², Th. Karakostas², W. Weber¹, R. Averbeck¹, and H. Riechert¹ — ¹Infineon Technologies, D-81370 Munich, Germany — ²Aristotle University of Thessaloniki, Department of Physics, GR-54124 Thessaloniki, Greece

GaN-nanowires were grown on c-plane sapphire substrates by solid-source molecular beam epitaxy (MBE) employing a RF plasma source for the incorporation of nitrogen. The formation of nanowires is induced by a thin layer of Ni that is sputtered onto the substrates and annealed prior to the growth of GaN. The orientation of the nanowires is perpendicular to the substrate, and their length is fairly uniform. Cross-section transmission electron microscopy (XTEM) observations reveal that the nanowires are single crystalline and have a wurtzite structure. Growth under N-rich conditions proceeds in axial direction, i.e. the nanowires become longer. In contrast, under Ga-rich conditions the nanowires grow in radial direction, i.e. they become thicker. Under both conditions, the growth rate in the dominant direction (either axial or radial) is about two orders of magnitudes greater than the growth rate in the respective other direction. Thus, both length and diameter can be controlled by choosing the appropriate N/Ga-flux-ratio and growth duration.