Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 10: Quantum Dots and Wires: Preparation and Characterization II (mainly Arsenides)

HL 10.1: Talk

Monday, March 26, 2012, 11:15–11:30, EW 202

Crystal Structure Tuning of Au-catalyzed Nanowires grown by MBE — Andreas Rudolph, Marcello Soda, Dieter Schuh, Josef Zweck, Dominique Bougeard, and •Elisabeth Reiger — Institute for Experimental and Applied Physics, University of Regensburg

GaAs nanowires were grown by MBE using a thin Au layer as catalyst material. For individual nanowires we study the size and the chemical composition of the (post-growth) Au-Ga catalyst droplets as well as the crystal structure by HRTEM and EDX. We estimate the Ga-concentration of the catalyst droplets during growth and relate this value to the adopted crystal structure of the nanowires. Depending on the Ga-concentration we observe two different growth modes. For low Ga content the nanowires exhibit wurtzite crystal structure. For higher Ga concentrations (>60%) zincblende segments within a wurtzite matrix are formed. By adjusting the growth parameters of this second (pseudo-Ga) growth mode pure zincblende nanowires - as typically observed by the self-catalyzed / Ga-assisted growth technique - can be obtained