title: A technique for large-area position-controlled growth of GaAs nanowire arrays.
abstract: We demonstrate a technique for fabricating position-controlled, large-area arrays of vertical semiconductor nanowires (NWs) with adjustable periods and NW diameters. In our approach, a Au-covered GaAs substrate is first coated with a thin film of photoresponsive azopolymer, which is exposed twice to a laser interference pattern forming a 2D surface relief grating. After dry etching, an array of polymer islands is formed, which is used as a mask to fabricate a matrix of gold particles. The Au particles are then used as seeds in vapour-liquid-solid growth to create arrays of vertical GaAs NWs using metalorganic vapour phase epitaxy. The presented technique enables producing NWs of uniform size distribution with high throughput and potentially on large wafer sizes without relying on expensive lithography techniques. The feasibility of the technique is demonstrated by arrays of vertical NWs with periods of 255-1000 nm and diameters of 50-80 nm on a 2 × 2 cm area. The grown NWs exhibit high long range order and good crystalline quality. Although only GaAs NWs were grown in this study, in principle, the presented technique is suitable for any material available for Au seeded NW growth.
authors.affiliation: Department of Micro- and Nanosciences, Micronova, Aalto University, PO Box 13500, FI-00076 Aalto, Finland.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Kauppinen
authors.forename: Tuomas
authors.initials: T
authors.lastname: Haggren
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Kravchenko
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: Teppo
authors.initials: T
authors.lastname: Huhtio
authors.forename: Esko
authors.initials: E
authors.lastname: Kauppinen
authors.forename: Veer
authors.initials: V
authors.lastname: Dhaka
authors.forename: Sami
authors.initials: S
authors.lastname: Suihkonen
authors.forename: Matti
authors.initials: M
authors.lastname: Kaivola
authors.forename: Harri
authors.initials: H
authors.lastname: Lipsanen
authors.forename: Markku
authors.initials: M
authors.lastname: Sopanen