Online proceedings - EDA Publishing Association

11-13
May 2011, Aix-en-Provence, France
Integration of Ferroelectric BaTiO 3 on Metallic Ni
Tapes for Power Generation
Greg Collins, Emanuel Silva, Ming Liu, David Elam, Chunrui Ma,
Andrey Chabanov, Arturo Ayon and Chonglin Chen
The University of Texas at San Antonio
One UTSA Circle
San Antonio, TX 78249, USA
Jie He, Jiechao Jiang and Efstathios Meletis
The University of Texas at Arlington
Arlington, TX 76019, USA
Abstract- Ferroelectric BaTiO 3 thin films were integrated
directly on metallic Ni tapes by using pulsed laser for energy
harvesting applications. Microstructure studies from x-ray
diffraction and electron microscopy indicate that the as-grown
BaTiO 3 thin films have pure BaTiO 3 crystal phase which
consists of the crystalline assemblage of nanopillars with
average cross sections from 100 nm to 200 nm directly on the
Ni tapes. The BaTiO 3 films have good interface structures and
strong adhesion to the Ni metallic tapes. Dielectric
measurements have shown the hysteresis loop at room
temperature in the film with a large remnant polarization,
indicating that the ferroelectric domains have been created in
the as-deposited BTO films. The successful integration of
ferroelectric thin films directly on metallic materials is
considered to be very promising for the development of
energy harvesting devices.
I. INTRODUCTION
Ferroelectric materials have been considered as the most
important materials for energy harvesting and data
storage due to their high dielectric constant and good
insulating properties. Among them, Barium Titanate,
BaTiO 3 (BTO), is one of the most important ferroelectric
materials that has attracted great attention for its remarkable
characteristics including high dielectric constant, good
ferroelectric properties, and large electro-optic and nonlinear
optic coefficients. Furthermore, this material has
excellent piezoelectric properties resulting in broad
applications in control systems, structural health monitoring
and energy harvesting. Therefore, the major challenge is to
successfully integrate BTO thin films directly on metallic
substrates with optimum metal/film interface properties for
various device applications such as supercapacitance and
power generation, among others. In fact, various techniques
have been developed to fabricate ferroelectric BTO thin
film for device fabrications.
Recently, BTO thin films have been deposited on various
substrates including oxide single crystal and semiconductor
substrates using a variety of techniques such as pulsed laser
deposition (PLD), hydrothermal method, sol-gel processing,
solid-state reactions, and metal-organic chemical vapor
deposition [1-6]. However, many challenges remain,
especially the interface-related issue observed when
fabricating ferroelectric thin films on structural materials
(steel, aluminum, titanium, etc.) for energy harvesting
device development. Publications describing the fabrication
of ferroelectric thin films on metallic materials were not
available until the reports of our recent achievements of insitu
fabrication of BTO thin films on the typical structural
material Ni using PLD system [7-8]. In the report contained
herein, we describe our recent achievements on the
fabrication of ferroelectric BTO thin films directly on
metallic Ni tapes with good crystallinity and excellent
dielectric properties.
II. EXPERIMENTAL
BaTiO 3 thin films were deposited on amorphous nickel
substrates in a PLD system using a KrF excimer laser with a
wavelength of 248 nm with an energy density of about 2.5
J/cm 2 and a laser repetition rate of 5Hz. The BTO thin films
were fabricated with details that can be found from the
literatures [7-8]. X-ray diffraction (XRD) was employed to
understand the crystal phases and the transmission electron
microscopy (TEM), plan-view and cross-section, were
employed to study the microstructure of the as-grown films
and interfacial layers. The dielectric properties were
characterized by using a Radiant RT6000 for understanding
the physical properties of the as-grown films and an Agilent
AFM/PFM with lock-in amplifier was used to observe the
piezoelectric response.
III. CHARACTERIZATION
Fig. 1 is the XRD θ-2θ pattern from the as-deposited
BTO thin film on Ni showing that all the peaks are from the
polycrystalline BTO phases and polycrystalline Ni
substrate. These peak positions suggest that the Ni substrate
is cubic phase and the BTO layer belongs the tetragonal
phase.
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