Open AccessSpectroscopic ellipsometry as an optical probe of strain evolution in ferroelectric thin films
Author(s) -
Dangyuan Lei,
Stéphane KénaCohen,
Bin Zou,
Peter K. Petrov,
Yannick Sonnefraud,
Jonathan Breeze,
Stefan A. Maier,
Neil McN. Alford
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.004419
Subject(s) - materials science , ferroelectricity , dielectric , thin film , ellipsometry , strain (injury) , relaxation (psychology) , optics , epitaxy , strain engineering , crystal (programming language) , substrate (aquarium) , single crystal , optoelectronics , silicon , crystallography , composite material , nanotechnology , layer (electronics) , chemistry , computer science , psychology , social psychology , medicine , programming language , physics , oceanography , geology
Heteroepitaxial strain in ferroelectric thin films is known to have a significant impact on both their low and high frequency dielectric properties. In this paper, we use ex-situ spectroscopic ellipsometry to study the strain evolution with film thickness, and strain relaxation in ferroelectric Ba0.5Sr0.5<TiO3 epitaxial films grown on single crystal substrates. For films grown on MgO substrates, a critical thickness for strain relaxation is observed. In addition, studies of Ba0.5Sr0.5<TiO3 films grown on different single crystal substrates reveal that the strain relaxation rate can be inferred from changes in the optical properties. Using this information, we show that the optical constants of Ba0.5Sr0.5<TiO3 can be readily tuned via strain engineering.