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The morphology, structure and phonon properties of well-aligned and kink-free GaAs nanowires grown on (1¯ 1¯ 1¯)B GaAs are reported. The nanowires were grown at temperatures down to 400 °C by Au-catalysed MOVPE using tBuAsH2 and Me3Ga in H2 ambient. Colloidal Au nanoparticles (NPs) with average size of 60–70 nm were used as catalyst. Below 425 °C the nanowires consist of almost cylindrical segments, their average diameter closely matching that of the original Au NPs. At higher temperatures, the nanowires show a large tapering. The structural analysis of nanowire samples grown at 450 °C evidences that residual catalyst droplets at the nanowire tips consist of crystalline fcc Au, with a preferred (1 1 1) crystallographic orientation, and orthorhombic GaAu2 alloy (γ phase). Non-resonant Raman scattering experiments carried out on GaAs nanowires showed no evidence of phonon confinement …
Publication date: 
1 Jan 2007

P Paiano, P Prete, E Speiser, N Lovergine, W Richter, L Tapfer, AM Mancini

Biblio References: 
Volume: 298 Pages: 620-624
Journal of crystal growth