title: Interface dynamics and crystal phase switching in GaAs nanowires.
abstract: Controlled formation of non-equilibrium crystal structures is one of the most important challenges in crystal growth. Catalytically grown nanowires are ideal systems for studying the fundamental physics of phase selection, and could lead to new electronic applications based on the engineering of crystal phases. Here we image gallium arsenide (GaAs) nanowires during growth as they switch between phases as a result of varying growth conditions. We find clear differences between the growth dynamics of the phases, including differences in interface morphology, step flow and catalyst geometry. We explain these differences, and the phase selection, using a model that relates the catalyst volume, the contact angle at the trijunction (the point at which solid, liquid and vapour meet) and the nucleation site of each new layer of GaAs. This model allows us to predict the conditions under which each phase should be observed, and use these predictions to design GaAs heterostructures. These results could apply to phase selection in other nanowire systems.
authors.affiliation: Solid State Physics and NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.|Centre for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Jacobsson
authors.affiliation: Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.|IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Federico
authors.initials: F
authors.lastname: Panciera
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Jerry
authors.initials: J
authors.lastname: Tersoff
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Reuter
authors.affiliation: Solid State Physics and NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Lehmann
authors.affiliation: Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
authors.forename: Stephan
authors.initials: S
authors.lastname: Hofmann
authors.affiliation: Solid State Physics and NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.|Centre for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Dick
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Frances M
authors.initials: FM
authors.lastname: Ross