Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena
HL 43.5: Poster
Tuesday, March 27, 2012, 09:30–12:30, Poster D
Vapor-solid growth of InAs nanowires on GaAs substrates by MBE — •Torsten Rieger1,2, Mihail Ion Lepsa1,2, Thomas Schäpers1,2, and Detlev Grützmacher1,2 — 1Peter Grünberg Institute - 9, Forschungszentrum Jülich, 52425 Jülich, Germany — 2JARA-Fundamentals of Future Information Technology
There are two general regimes for the growth of self-catalyzed InAs nanowires (NWs) on GaAs (111)B substrates covered with SiOx: (1) low V/III ratio and high substrate temperature and (2) high V/III ratio and low substrate temperature. In the first regime, the NW growth is due to an In droplet while in the second one, the NWs grow without a droplet in the vapor-solid mode. Here, we present a detailed study about the vapor-solid growth of InAs NWs. It is found that the appropriate SiOx layer thickness is important to achieve a high density of vertical NWs. When the thickness is higher than 5 nm, the NW density is low and they tend to grow tilted. At SiOx thicknesses around 4 nm, the density is between 10 and 20 NW/µm2. The NW length is influenced by both In and As4 beam fluxes. The length distribution is broad while the distribution of the NW diameters is narrow. Diameters down to 30 nm are achieved. Finally, the influence of the growth parameters on the crystal structure of the InAs NWs is described.