Influence of Alumina Addition on the Optical Properties and the Thermal Stability of Titania Thin Films and Inverse Opals Produced by Atomic Layer Deposition
Martin Waleczek,
Jolien Dendooven,
Pavel Dyachenko,
Alexander Y. Petrov,
Manfred Eich,
Robert H. Blick,
Christophe Detavernier,
Kornelius Nielsch,
Kaline P. Furlan,
Robert Zierold
Affiliations
Martin Waleczek
Institute of Nanostructure and Solid State Physics & Center for Hybrid Nanostructures, Universität Hamburg, Luruper Chausse 149, 22761 Hamburg, Germany
Jolien Dendooven
Department of Solid State Sciences, COCOON Group, Ghent University, Krijgslaan 281/S1, B-9000 Ghent, Belgium
Institute of Optical and Electronic Materials, Hamburg University of Technology, Eißendorfer Str. 38, 21073 Hamburg, Germany
Manfred Eich
Institute of Optical and Electronic Materials, Hamburg University of Technology, Eißendorfer Str. 38, 21073 Hamburg, Germany
Robert H. Blick
Institute of Nanostructure and Solid State Physics & Center for Hybrid Nanostructures, Universität Hamburg, Luruper Chausse 149, 22761 Hamburg, Germany
Christophe Detavernier
Department of Solid State Sciences, COCOON Group, Ghent University, Krijgslaan 281/S1, B-9000 Ghent, Belgium
Kornelius Nielsch
Institute of Materials Science, Technical University Dresden, Helmholtzstr. 10, 01069 Dresden, Germany
Kaline P. Furlan
Institute of Nanostructure and Solid State Physics & Center for Hybrid Nanostructures, Universität Hamburg, Luruper Chausse 149, 22761 Hamburg, Germany
Robert Zierold
Institute of Nanostructure and Solid State Physics & Center for Hybrid Nanostructures, Universität Hamburg, Luruper Chausse 149, 22761 Hamburg, Germany
TiO2 thin films deposited by atomic layer deposition (ALD) at low temperatures (2 parts is known to alter phase transitions and to stabilize crystalline phases. In this work, we have developed low-temperature ALD super-cycles to introduce Al2O3 into TiO2 thin films and photonic crystals. The aluminum oxide content was adjusted by varying the TiO2:Al2O3 internal loop ratio within the ALD super-cycle. Both thin films and inverse opal photonic crystal structures were subjected to thermal treatments ranging from 200 to 1200 °C and were characterized by in- and ex-situ X-ray diffraction, spectroscopic ellipsometry, and spectroscopic reflectance measurements. The results show that the introduction of alumina affects the crystallization and phase transition temperatures of titania as well as the optical properties of the inverse opal photonic crystals (iPhC). The thermal stability of the titania iPhCs was increased by the alumina introduction, maintaining their photonic bandgap even after heat treatment at 900 °C and outperforming the pure titania, with the best results being achieved with the super-cycles corresponding to an estimated alumina content of 26 wt.%.
