title: Catalyst shape engineering for anisotropic cross-sectioned nanowire growth.
abstract: The ability to engineer material properties at the nanoscale is a crucial prerequisite for nanotechnology. Hereunder, we suggest and demonstrate a novel approach to realize non-hemispherically shaped nanowire catalysts, subsequently used to grow InP nanowires with a cross section anisotropy ratio of up to 1:1.8. Gold was deposited inside high aspect ratio nanotrenches in a 5 nm thick SiNxselective area mask; inside the growth chamber, upon heating to 455 °C, the thin gold stripes agglomerated, resulting in an ellipsoidal dome (hemiellipsoid). The initial shape of the catalyst was preserved during growth to realize asymmetrically cross-sectioned nanowires. Moreover, the crystalline nature of the nanowire side facets was found to depend on the nano-trench orientation atop the substrate, resulting in hexagonal or octagonal cross-sections when the nano-trenches are aligned or misaligned with the [1̄10] orientation atop a [111]B substrate. These results establish the role of catalyst shape as a unique tool to engineer nanowire growth, potentially allowing further control over its physical properties.
authors.affiliation: Department of Electrical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Yonatan
authors.initials: Y
authors.lastname: Calahorra
authors.affiliation: Department of Electrical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kelrich
authors.affiliation: Department of Electrical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Shimon
authors.initials: S
authors.lastname: Cohen
authors.affiliation: Department of Electrical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Ritter