Structure and Morphology in Diffusion-Driven Growth of Nanowires: The Case of ZnTe

• Published in: Nano letters 2014-04, Vol.14 (4), p.1877-1883
• Main Authors: Rueda-Fonseca, P, Bellet-Amalric, E, Vigliaturo, R, den Hertog, M, Genuist, Y, André, R, Robin, E, Artioli, A, Stepanov, P, Ferrand, D, Kheng, K, Tatarenko, S, Cibert, J
• Format: Article
• Language: English
• Subjects: Catalytic methods; Condensed matter: structure, mechanical and thermal properties; Craters; Cross-disciplinary physics: materials science; rheology; Cylinders; Diffusion in nanoscale solids; Diffusion in solids; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Methods of nanofabrication; Morphology; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanostructure; Nanowires; Physics; Polarity; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Transport properties of condensed matter (nonelectronic); Wurtzite; Zinc tellurides
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl4046476

Gold-catalyzed ZnTe nanowires were grown at low temperature by molecular beam epitaxy on a ZnTe(111) B buffer layer, under different II/VI flux ratios, including with CdTe insertions. High-resolution electron microscopy and energy-dispersive X-ray spectroscopy (EDX) gave information about the crystal structure, polarity, and growth mechanisms. We observe, under stoichiometric conditions, the simultaneous presence of zinc-blende and wurtzite nanowires spread homogeneously on the same sample. Wurtzite nanowires are cylinder-shaped with a pyramidal-structured base. Zinc-blende nanowires are cone-shaped with a crater at their base. Both nanowires and substrate show a Te-ended polarity. Te-rich conditions favor zinc-blende nanowires, while Zn-rich suppress nanowire growth. Using a diffusion-driven growth model, we present a criterion for the existence of a crater or a pyramid at the base of the nanowires. The difference in nanowire morphology indicates lateral growth only for zinc-blende nanowires. The role of the direct impinging flux on the nanowire’s sidewall is discussed.