title: Nano-rescaling of gold films on polystyrene: thermal management for SERS.
abstract: Nano-textured Au surfaces were prepared on pre-stretched 2D polystyrene (PS) sheets sputtered with different thicknesses of Au. The Au-coated PS was subjected to thermal annealing above the glass transition temperature at ∼150 °C, thus undergoing surface area rescaling via a volume phase transition. The yellow color of the Au changed from the typical mirror-like appearance to a diffusive dark yellow, progressing to dark brown at the smallest feature size, hence, electromagnetic energy was coupled into the substrate. While the surface area footprint is the same after shrinking the PS, the roughness can be modified from the nano- to the micro-scale for different initial thicknesses of sputtered Au. The nanometer-sized features of surface wrinkles on the Au films make them suitable for surface-enhanced Raman scattering (SERS) sensors that can reach ∼104counts per s per mW. The thermal diffusivity of the contracted surfaces was determined by a non-contact temperature wave method and was larger than that of PS (α ≃ 1.1 × 10-7m2s-1) with a linear scaling on the Au thickness: each 10 nm addition of Au increased the diffusivity by 4%. This allows improved heat dissipation from the laser irradiated spot during SERS measurements.
authors.affiliation: School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia. abalcytis@swin.edu.au and Department of Laser Technologies, Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania.
authors.forename: Armandas
authors.initials: A
authors.lastname: Balčytis
authors.affiliation: Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan. morikawa.j.aa@m.titech.ac.jp.
authors.forename: Meguya
authors.initials: M
authors.lastname: Ryu
authors.affiliation: School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia. abalcytis@swin.edu.au.
authors.forename: Gediminas
authors.initials: G
authors.lastname: Seniutinas
authors.affiliation: ARC Training Centre in Biodevices, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Stoddart
authors.affiliation: School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia. abalcytis@swin.edu.au.
authors.forename: Md Abdullah
authors.initials: MA
authors.lastname: Al Mamun
authors.affiliation: Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan. morikawa.j.aa@m.titech.ac.jp.
authors.forename: Junko
authors.initials: J
authors.lastname: Morikawa
authors.affiliation: School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia. abalcytis@swin.edu.au and Center for Nanotechnology, King Abdulaziz University, Jeddah 21589, Saudi Arabia and Melbourne Centre for Nanofabrication, the Victorian Node of the Australian National Fabrication Facility, 151 Wellington Rd, Clayton, VIC 3168, Australia.
authors.forename: Saulius
authors.initials: S
authors.lastname: Juodkazis