Analysis of sub-bandgap losses in TiO2 coating deposited via single and dual ion beam deposition

0475292 - ÚFP 2018 RIV CH eng J - Journal Article
Žídek, Karel - Hlubuček, Jiří - Horodyská, Petra - Budasz, Jiří - Václavík, Jan
Analysis of sub-bandgap losses in TiO2 coating deposited via single and dual ion beam deposition.
Thin Solid Films. Roč. 626, March (2017), s. 60-65. ISSN 0040-6090. E-ISSN 1879-2731
R&D Projects: GA MŠMT(CZ) LO1206
Institutional support: RVO:61389021
Keywords : Ion beam deposition * Titanium dioxide * Optical coating * Sub-bandgap losses * Urbach tail
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 1.939, year: 2017
http://www.sciencedirect.com/science/article/pii/S0040609017301256

We present a detailed study of sub-bandgap losses in TiO2 optical coatings prepared by using a single and a dual ion beam deposition. By extracting high-precision spectra of the losses in the TiO2 layers deposited under varied parameters we were able to study the losses in great detail. We were able to identify several spectral features and discuss their origin. Additional experiments allowed us to determine the contribution of absorption and scattering to the losses, as well as to discern whether the observed losses have volume or interface character. The results reveal that the dominant source of absorption in the high-quality samples is volume absorption originating from the so-called Urbach tail. We discuss the limitations imposed by the Urbach tail.
Permanent Link: http://hdl.handle.net/11104/0272133