title: Bundling of GaAs nanowires: a case of adhesion-induced self-assembly of nanowires.
abstract: The origin of deflections of semiconductor nanowires (NWs) induced by an electron beam in scanning electron microscopy has been subject to different interpretations. Similarly, the subsequent clumping together of NWs into bundles is frequently observed, but no interpretation has yet been advanced. Here we present results on the bundling of NWs following the intentional bending by an electron beam. Furthermore, we extend the concept of lateral collapse, usually applied to fibrillar architectures mimicking the adhesiveness of natural surfaces (the so-called Gecko effect), to analyze the mechanism of the NW bundle formation. We demonstrate how the geometry of the NW arrays and the mechanical properties of the composing materials govern bundling and how these parameters should be taken into account in the design of NW arrays both for avoiding vertical misalignment when detrimental and for achieving patterning of NW arrays into nanoarchitectures.
authors.affiliation: Department of Physics and Astronomy, University of Bologna , Viale Berti Pichat 6/2, Bologna, I-40127, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Carapezzi
authors.forename: Giacomo
authors.initials: G
authors.lastname: Priante
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Grillo
authors.forename: Laurent
authors.initials: L
authors.lastname: Montès
authors.forename: Silvia
authors.initials: S
authors.lastname: Rubini
authors.forename: Anna
authors.initials: A
authors.lastname: Cavallini
keywords: adhesion; nanoarchitectonics; nanowire arrays; self-assembly; surface engineering