title: Direct-write deposition and focused-electron-beam-induced purification of gold nanostructures.
abstract: Three-dimensional gold (Au) nanostructures offer promise in nanoplasmonics, biomedical applications, electrochemical sensing and as contacts for carbon-based electronics. Direct-write techniques such as focused-electron-beam-induced deposition (FEBID) can provide such precisely patterned nanostructures. Unfortunately, FEBID Au traditionally suffers from a high nonmetallic content and cannot meet the purity requirements for these applications. Here we report exceptionally pure pristine FEBID Au nanostructures comprising submicrometer-large monocrystalline Au sections. On the basis of high-resolution transmission electron microscopy results and Monte Carlo simulations of electron trajectories in the deposited nanostructures, we propose a curing mechanism that elucidates the observed phenomena. The in situ focused-electron-beam-induced curing mechanism was supported by postdeposition ex situ curing and, in combination with oxygen plasma cleaning, is utilized as a straightforward purification method for planar FEBID structures. This work paves the way for the application of FEBID Au nanostructures in a new generation of biosensors and plasmonic nanodevices.
authors.affiliation: Institute of Solid State Electronics, Vienna University of Technology , Floragasse 7/1, A-1040 Vienna, Austria.
authors.forename: Domagoj
authors.initials: D
authors.lastname: Belić
authors.forename: Mostafa M
authors.initials: MM
authors.lastname: Shawrav
authors.forename: Marco
authors.initials: M
authors.lastname: Gavagnin
authors.forename: Michael
authors.initials: M
authors.lastname: Stöger-Pollach
authors.forename: Heinz D
authors.initials: HD
authors.lastname: Wanzenboeck
authors.forename: Emmerich
authors.initials: E
authors.lastname: Bertagnolli
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry; D004583:Electrons; D006046:Gold / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D006046:Gold
keywords: FEBIC; FEBID; gold nanostructure; nanopillar; nanowire; oxygen plasma cleaning; purity