title: Bottom-up Fabrication of Multilayer Stacks of 3D Photonic Crystals from Titanium Dioxide.
abstract: A strategy for stacking multiple ceramic 3D photonic crystals is developed. Periodically structured porous films are produced by vertical convective self-assembly of polystyrene (PS) microspheres. After infiltration of the opaline templates by atomic layer deposition (ALD) of titania and thermal decomposition of the polystyrene matrix, a ceramic 3D photonic crystal is formed. Further layers with different sizes of pores are deposited subsequently by repetition of the process. The influence of process parameters on morphology and photonic properties of double and triple stacks is systematically studied. Prolonged contact of amorphous titania films with warm water during self-assembly of the successive templates is found to result in exaggerated roughness of the surfaces re-exposed to ALD. Random scattering on rough internal surfaces disrupts ballistic transport of incident photons into deeper layers of the multistacks. Substantially smoother interfaces are obtained by calcination of the structure after each infiltration, which converts amorphous titania into the crystalline anatase before resuming the ALD infiltration. High quality triple stacks consisting of anatase inverse opals with different pore sizes are demonstrated for the first time. The elaborated fabrication method shows promise for various applications demanding broadband dielectric reflectors or titania photonic crystals with a long mean free path of photons.
authors.affiliation: Institute of Advanced Ceramics, Hamburg University of Technology (TUHH) , Denickestrasse 15, 21073 Hamburg, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Kubrin
authors.affiliation: Institute of Advanced Ceramics, Hamburg University of Technology (TUHH) , Denickestrasse 15, 21073 Hamburg, Germany.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Pasquarelli
authors.affiliation: Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11, 20355 Hamburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Waleczek
authors.affiliation: Institute of Optical and Electronic Materials, Hamburg University of Technology , Eissendorfer Strasse 38, 21073 Hamburg, Germany.
authors.forename: Hooi Sing
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11, 20355 Hamburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Zierold
authors.affiliation: Institute of Advanced Ceramics, Hamburg University of Technology (TUHH) , Denickestrasse 15, 21073 Hamburg, Germany.
authors.forename: Jefferson J
authors.initials: JJ
authors.lastname: do Rosário
authors.affiliation: Institute of Optical and Electronic Materials, Hamburg University of Technology , Eissendorfer Strasse 38, 21073 Hamburg, Germany.
authors.forename: Pavel N
authors.initials: PN
authors.lastname: Dyachenko
authors.affiliation: Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11, 20355 Hamburg, Germany.
authors.forename: Josep M
authors.initials: JM
authors.lastname: Montero Moreno
authors.affiliation: Institute of Optical and Electronic Materials, Hamburg University of Technology , Eissendorfer Strasse 38, 21073 Hamburg, Germany.|ITMO University , Kronverkskii Avenue 49, 197101, St. Petersburg, Russia.
authors.forename: Alexander Yu
authors.initials: AY
authors.lastname: Petrov
authors.affiliation: Institute of Advanced Ceramics, Hamburg University of Technology (TUHH) , Denickestrasse 15, 21073 Hamburg, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Janssen
authors.affiliation: Institute of Optical and Electronic Materials, Hamburg University of Technology , Eissendorfer Strasse 38, 21073 Hamburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Eich
authors.affiliation: Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11, 20355 Hamburg, Germany.|Institute for Metallic Materials, Leibniz Institute for Solid State and Materials Research Dresden , Helmholtzstrasse 20, 01609 Dresden, Germany.
authors.forename: Kornelius
authors.initials: K
authors.lastname: Nielsch
authors.affiliation: Institute of Advanced Ceramics, Hamburg University of Technology (TUHH) , Denickestrasse 15, 21073 Hamburg, Germany.
authors.forename: Gerold A
authors.initials: GA
authors.lastname: Schneider
keywords: 3D photonic crystals; atomic layer deposition; broadband dielectric reflectors; inverse opals; titanium dioxide