In-line picogram-resolution microchannel resonator for protein adsorption measurements operating at atmospheric pressure

This paper reports on an in-line microchannel resonator for protein adsorption measurement with a resolution of 19 pg. The sensor eliminates the need for complex measurement sequences, vacuum environment or delicate external (optical) components

Ferroelectric properties of epitaxial Pb(Zr, Ti)O3 thin films on silicon by control of crystal orientation

Crystalline Pb(Zr,Ti)O3 (PZT) thin films between metallic-oxide SrRuO3 (SRO) electrodes were prepared using pulsed laser deposition on CeO2/yttria-stabilized zirconia buffered silicon (001) substrates. Different deposition conditions for the initial layers of the bottom SRO electrode result in an orientation switch. Either (110)- or (001)-oriented SRO thin films are obtained and the PZT films deposited on the bottom electrode continued both growth directions. The ferroelectric characteristics of the SRO/PZT/SRO capacitors are found to be strongly dependent on their crystalline orientation: PZT (001)-oriented thin films showed stable, high quality ferroelectric response, while the remnant polarization of the PZT (110)-oriented thin films only show high response after multiple switching cycles

Misfit strain dependence of ferroelectric and piezoelectric properties of clamped (001) epitaxial Pb(Zr0.52,Ti0.48)O3 thin films \ud

A study on the effects of the residual strain in Pb(Zr0.52Ti0.48)O3 (PZT) thin films on the ferroelectric and piezoelectric properties is presented. Epitaxial (001)-oriented PZT thin film capacitors are sandwiched between SrRuO3 electrodes. The thin film stacks are grown on different substrate-buffer-layer combinations by pulsed laser deposition. Compressive or tensile strain caused by the difference in thermal expansion of the PZT film and substrate influences the ferroelectric and piezoelectric properties. All the PZT stacks show ferroelectric and piezoelectric behavior that is consistent with the theoretical model for strained thin films in the ferroelectric r-phase. We conclude that clamped (001) oriented Pb(Zr0.52Ti0.48)O3 thin films strained by the substrate always show rotation of the polarization vecto

Domain tilting, domain fractions and substrate-induced strain in epitaxial tetragonal Pb(Zr,Ti)O3 thin films

A relation is established between the domain fraction, the domain inclination and the substrate-induced strain of epitaxial PZT thin films, in the tetragonal phase towards the morphotropic phase boundary (Zr-content 1-x=0.2, 0.4, 0.45). The substrate-induced strain is controlled through thermal expansion coefficient mismatch between film and the silicon, KTaO3, DyScO3 and SrTiO3 substrates. A poly domain structure is found by reciprocal space mapping and piezo force microscopy, for which the domain fraction depends strongly on strain, while the lattice strain remains constant. The concept of the effective substrate and a new model based on geometrical arguments is used to derive the volume fraction directly from the lattice parameters. A fit to the x-ray diffraction intensity data is found. Next to the tilted a and b-domains, we observe c-domains which are tilted in both the a and b-direction. The same geometrical model describes this simultaneous buckling of in-plane and out-of-plane domains as function of strain. Furthermore, indications for an increase of the domain-wall width as function of Zrcontent have been obtained

Thickness dependence of ferroelectric and piezoelectric properties in epitaxial PZT thin films

Epitaxial (110)-oriented Pb(Zr0.52,Ti0.48)O3 (PZT) thin films were fabricated on SrRuO3-coated (001) YSZ/Si and SrRuO3-coated (110) SrTiO3 (STO) substrates with various thicknesses ranging from 0.1 μm to 1.0 μm by pulsed laser deposition. The effects of the film thickness on the structure, ferroelectric and piezoelectric properties were systematically investigated as a function of the film thickness. On the STO substrate the remnant polarization of the films increased from 36.6 to 45.5 μC/cm2 with the increasing film thickness, while in the films on the silicon substrate the remnant polarization was in the range of 12.4 - 20.2μC/cm2. The improvement of the remnant polarization with increasing film thickness was due to the reduction of the film/electrode interface effect which leads to improve the switching of domains. The films on the STO substrate were in a compressive stress, while in the films on the silicon substrate a higher tensile stress was found. Compressive stress causes the ferroelectric domains to orient along the longitudinal direction (c-domain orientation), which in turn can result in an increase of the polarization. Moreover, the effective piezoelectric coefficient of the PZT thin films increased steady with increasing thickness. This effect is likely related to a mechanism of elastic domains that can move more easily in thicker film, and that give rise to out-ofplane piezoelectric displacement

Advance engineered piezoelectric materials for energy harvesting devices

Piezoelectric materials offer a number of advantages in energy harvesting systems, by transforming ambient vibration into electrical energy, which can be stored and power other devices. To improve energy harvesting device performance, the figure of merit (e312/ ) is vital to achieve a higher piezoelectric voltage and maximum the power output. In this study, Pb(Zr1-xTix)O3 (PZT) was chosen for its prime piezoelectric properties, such as their high piezoelectric coefficients, high power output density and relatively low epsilon. Epitaxial PZT thin films with controlled orientations are achieved on silicon substrates by pulsed laser deposition (PLD). Pb(Zr1-xTix)O3 thin films with variety of dielectric constant () and piezoelectric coefficient (e31, d33), were studied and compared with each other. We found very large figure of merit values within these engineered piezoelectric thin films. Using optimized composition, crystal orientation and strain, maximum values of 20.4 3 C/m2 were found.. A shift of morphotropic phase boundary (MPB) is observed in the perovskite thin film structure, which is due to the residual strain caused by the different thermal expansion coefficients between PZT thin films and silicon substrates. These results show that for epitaxial PZT thin films, the composition of the PZT should be optimized to compensate the strain state. Besides the characterization of material properties, energy harvesting devices are also being fabricated and will be discussed in the contribution