Piezoelectric Thin Films

Book Description This monograph covers the fundamentals, fabrication, testing, and modeling of ambient energy harvesters based on three main streams of energy-harvesting mechanisms: piezoelectrics, ferroelectrics, and pyroelectrics. It addresses their commercial and biomedical applications, as well as the latest research results. Graduate students, scientists, engineers, researchers, and those new to the field will find this book a handy and crucial reference because it provides a comprehensive perspective on the basic concepts and recent developments in this rapidly expanding field.

Pulse detonation is a propulsion technology that involves detonation of fuel to produce thrust more efficiently than current engine systems. By literature survey and library research it is shown that Pulse Detonation Engine (PDE) technology is more efficient than current engine types by virtue of its mechanical simplicity and thermodynamic efficiency. As the PDE produces a higher specific thrust than comparable ramjet, scramjet engines at speeds of up to approximately Mach 2.3 to Mach 5, it is suitable for use as part of a multi-stage propulsion system. The PDE can provide static thrust for a ramjet or scramjet engine, or operate in combination with turbofan systems. As such, it sees potential applications in many sectors of the aerospace, aeronautic, and military industries. However, there remain engineering challenges that must be overcome before the PDE can see practical use. Current methods for initiating the detonation process need refinement. To this end, many government research bodies and a few private organizations around the world are working on PDS research & further development.

This paper focuses on the primary development of novel numerical and analytical techniques of the modal damped vibration energy harvesters with arbitrary proof mass offset. The key equations of electromechanical finite element discretisation using the extended Lagrangian principle are revealed and simplified to give matrix and scalar forms of the coupled system equations, indicating the most relevant numerical technique for the power harvester research. To evaluate the performance of the numerical study, the analytical closed-form boundary value equations have been developed using the extended Hamiltonian principle. The results from the electromechanical frequency response functions (EFRFs) derived from two theoretical studies show excellent agreement with experimental studies. The benefit of the numerical technique is in providing effective and quick predictions for analysing parametric designs and physical properties of piezoelectric materials. Although analytical technique provides a challenging process for analysing the complex smart structure, it shows complementary study for validating the numerical technique.

The electro-mechanical impedance (EMI) technique has so far been very successful in monitoring structural components made of both metals and nonmetals in the fields of civil, mechanical and aerospace engineering. In the last two decades, researchers have reported fairly good results using the EMI technique through costly conventional hardware, such as impedance analyzer and LCR meter. This paper evaluates the performance of the low-cost miniature impedance chip AD5933 for structural health monitoring (SHM) of prototype structures. Most studies involving AD5933 have so far been restricted to miniature metal structures only, and in particular, no study has so far been reported on reinforced concrete (RC) structures. In this investigation, experiments are first conducted on a real-life sized reinforced concrete (RC) beam, 150×210×4000 mm in size, instrumented with 19 pairs of piezoelectric ceramic (PZT) patches in embedded configuration, aiming to detect and locate incipient to severe damages. Experimental investigations are then extended to a large mild steel plate structure, 1200×970×8 mm in size, divided into 30 equal panels and instrumented with one PZT patch at each node. The results of the two studies confirm that the low cost miniature impedance chip is suitable for level one damage diagnosis in large prototype structures, both steel as well as RC. It is however not suitable for higher level analysis involving extraction of the structural impedance parameters.

Presented here is a patent in the Bulgarian register of inventions (Reg. № 41177/1978), written in Bulgarian. The patent relates to uniform deposition of semiconducting and insulating thin films in cold gas plasma. Various flat substrates can be used, semiconductor ones in particular. The claims relate to a specific configuration of the reactor chamber by which uniformity of the (static part of) gas plasma is achieved. That feature results in improved uniformity of the thus deposited thin films, as compared to the one achieved by the existing systems. The application of this method is demonstrated on Si3N4 and SiO2 thin layers deposited onto Silicon wafers, aimed for the mass production of MOS IC’s (Metal-Oxide-Semiconductor Integrated Circuits).

The invention described features one claim. The description is supported by two drawings.

After a piezoelectric inkjet printhead jets the first droplet, the actuating membrane still vibrates, creating residual vibrations in the ink channel, which can degrade the inkjet printhead performance. For suppressing these vibrations, an optimized actuating voltage waveform with two pulses must be obtained, of which the first pulse is used for jetting and the second pulse is used to suppress the residual vibrations. In this study, the pressure history within the ink channel of a recirculating piezoelectric inkjet printhead was first acquired using lumped element modeling. Then, for suppressing residual vibrations, a bipolar voltage waveform was optimized via analysis of the tuning time (t t), dwell time (t d2), rising time (t r2), falling time (t f2), and voltage amplitude of the second pulse. Two voltage waveforms, Waveform 01 and Waveform 02, were optimized thereafter. In Waveform 01, t t = 2 µs, t d2 = 2 µs, and t r2 and t f2 = 1 µs were finalized as the optimal parameters; in the case of another waveform, the optimal parameters of t d2 , t r2 , and t f2 were found to be 4, 1, and 1 µs, respectively. The optimal voltage amplitude of the second pulse was found to be 1/3 the amplitude of the first pulse. On the basis of our analysis, the tuning time in Waveform 01 is the most sensitive parameter, and the performance yielded is even poorer than that yielded by standard waveform, if not optimized. Therefore, the other waveform is recommended for the suppression of residual vibrations.

This paper describes the implementation of LabVIEW software to control instruments and acquire data from a piezoelectric energy harvesting test station which is based on a cantilever structure. The experiment is run in the Clean Energy Laboratory on the Ambient Energy Harvester Test Station. A digital multimeter, a programmable resistance selector, an arbitrary waveform generator, a shaker table, an accelerometer and a laser displacement sensor are used to control and acquire data in terms of harvested energy as a function of vibration frequency and load resistance. LabVIEW software is used to control the test station which makes near real-time data measurements, displays waveforms on a PC screen, and stores data for later analysis. Acquired waveforms are presented in terms of frequency versus voltage of the vibrating cantilever at preselected ranges of load resistances in terms of either AC or DC voltages. The vibration of the cantilever beam is measured with an accelerometer and b...

This paper describes the implementation of LabVIEW software to control instruments and acquire data from a piezoelectric energy harvesting test station which is based on a cantilever structure. The experiment is run in the Clean Energy Laboratory on the Ambient Energy Harvester Test Station. A digital multimeter, a programmable resistance selector, an arbitrary waveform generator, a shaker table, an accelerometer and a laser displacement sensor are used to control and acquire data in terms of harvested energy as a function of vibration frequency and load resistance. LabVIEW software is used to control the test station which makes near real-time data measurements, displays waveforms on a PC screen, and stores data for later analysis. Acquired waveforms are presented in terms of frequency versus voltage of the vibrating cantilever at preselected ranges of load resistances in terms of either AC or DC voltages. The vibration of the cantilever beam is measured with an accelerometer and b...

... Ecole Polytechnique Fédérale de Lausanne—EPFL, CH-1015 Lausanne, Switzerland 2 Hach Ultra Analytics, 1222 Vésenaz, Switzerland 3 Siemens Building Division, 8505 Mannedorf, Switzerland E-mail: paul.muralt@epfl ... J = −0.875e31,f (1−ν)wel E L3 t2 iω ˆp (cantilever) (5) ...

We report a multiple resonant mode film bulk acoustic resonator (FBAR) with different AlN film thicknesses of 605 nm, 640 nm and 680 nm. With the tilted c-axis orientation of the AlN piezoelectric film providing polarization vertical to the c-axis, acoustic wave resonant peaks have been observed for both the thickness shear modes (TSM 0th, TSM 1st, TSM 2nd) and the thickness extension modes (TEM 0th, TEM 1st). The corresponding parallel resonant frequencies are around 1.60 GHz, 2.41 GHz, 3.45 GHz, 2.75 GHz and 4.10 GHz, respectively. The latter two TEM modes also have good quality factors, and high equivalent electromechanical coupling coefficients Keff2 of 647, 3.13% and 113, 6.23%, respectively. By etching the 1.8 μm silicon sacrificial layer, the air gap FBAR devices have been fabricated in an easier and cleaner way resulting in a low insertion loss of −2.2 dB. The overall device structure of the top electrode/AlN film/bottom electrode on SiO2/silicon-on-insulator (SOI) substrate potentially enables CMOS compatibility. These multiple resonant mode FBAR devices will promote the integration of multi-band filters on a single chip. Improvements of the fabrication process, the influence of different AlN film thicknesses and theoretical analyses of the coexistence of multiple resonant modes are presented.

In this article, a piezoelectric energy harvesting has been developed experimentally and theoretically based on Euler-Bernoulli Theory. A PVDF piezoelectric thick film has attached along of clamped-clamped beam under sinusoidal base excitation of shaker. The results showed a good agreement between the experimental and simulation of suggested model. The voltage output frequency response function (FRF), current FRF, and output power has been studied under short and open circuit conditions at first vibration mode. The mode shape of the clamped-clamped beam for first three resonance frequency has been modeled and investigated using COMSOL Multiphysics and MATLAB.

El medidor de fuerza aquí presentado está constituido básicamente de tres etapas. La primera etapa (etapa sensor) está constituida por el sensor piezoresistivo FlexiForce modelo A201, que fue escogido debido a sus múltiples propiedades físicas y de funcionamiento.  En la segunda etapa, a través de un circuito divisor de voltaje, se transformó la variación de resistencia del sensor piezoresistivo en una variación de voltaje. Debido a que los voltajes generados por el circuito divisor de voltaje eran pequeños, se resolvió utilizar un amplificador de instrumentación para amplificar dicha señal. Por último, la etapa tres abarca todo lo relacionado con la visualización de la medida a realizar. Para lograr que la medida de fuerza se mostrara en la pantalla de una PC se diseñó un programa, a través del software LabView, que muestra de manera gráfica y numérica el valor de la medida realizada y su correspondiente unidad.

The transformation of vibrations into low-power electricity has received growing attention over the past couple of decades. The goal in this research field is to power wireless sensors and other small electronic components by harvesting ambient mechanical energy. Piezoelectricity is arguably the most popular transduction mechanism for converting mechanical vibrations into electrical energy. As a promising concept of piezoelectric energy conversion, smart paver tiles are proposed to harness human steps for energy harvesting and a wide range of critical sensing applications ranging from security to healthcare. In this work, we explore the use of a curved piezoelectric transducer (specifically a THUNDER ® configuration) for smart paver tiles both analytically and experimentally. Following the description of the smart paver tiles developed, an analytical model is developed and closed-form electromechanical frequency response functions are obtained. Experiments are performed for a range of excitation frequencies (1-10Hz), electrical load resistance values, and low force levels. It is shown that the first-order electromechanical model successfully represents the governing dynamics. Abstract The transformation of vibrations into low-power electricity has received growing attention over the past couple of decades. The goal in this research field is to power wireless sensors and other small electronic components by harvesting ambient mechanical energy. Piezoelectricity is arguably the most popular transduction mechanism for converting mechanical vibrations into electrical energy. As a promising concept of piezoelectric energy conversion, smart paver tiles are proposed to harness human steps for energy harvesting and a wide range of critical sensing applications ranging from security to healthcare. In this work, we explore the use of a curved piezoelectric transducer (specifically a THUNDER ® configuration) for smart paver tiles both analytically and experimentally. Following the description of the smart paver tiles developed, an analytical model is developed and closed-form electromechanical frequency response functions are obtained. Experiments are performed for a range of excitation frequencies (1-10Hz), electrical load resistance values, and low force levels. It is shown that the first-order electromechanical model successfully represents the governing dynamics.

After a piezoelectric inkjet printhead jets the first droplet, the actuating membrane still vibrates, creating residual vibrations in the ink channel, which can degrade the inkjet printhead performance. For suppressing these vibrations, an optimized actuating voltage waveform with two pulses must be obtained, of which the first pulse is used for jetting and the second pulse is used to suppress the residual vibrations. In this study, the pressure history within the ink channel of a recirculating piezoelectric inkjet printhead was first acquired using lumped element modeling. Then, for suppressing residual vibrations, a bipolar voltage waveform was optimized via analysis of the tuning time (tt ), dwell time (td2), rising time (tr2), falling time (tf2), and voltage amplitude of the second pulse. Two voltage waveforms, Waveform 01 and Waveform 02, were optimized thereafter. In Waveform 01, tt=2 μs, td2=2 μs, and tr2 and tf2=1 μs were finalized as the optimal parameters; in the case of a...

Based on an anisotropic phase field model, the morphological evolution and migration of inclusions in piezoelectric films under mechanical and electric loads are investigated. An order parameter field is introduced to characterize the evolution of inclusion in piezoelec-tric film, where the zero contour evolution of order parameter in the phase interface layer between inclusion and matrix film tracks the morphological change and migration of the inclusion driven by coupled mechanical and electric loads. Results show that morphological evolution and migration of inclusion in piezoelectric film is mainly caused by normal stress gradient in the phase interface layer between inclusions and piezoelectric film, and when piezoelectric film appears in a lower resistivity, an additional drive force induced by electron field (electron wind) exerted the piezoelectric film promotes the migration of an inclusion toward the higher electric potential direction. Anisotropic diffusion behavior of interface layer causes asymmetrically morphological evolution of inclusion in piezoelectric film under different loads.

We used pulsed laser deposition to grow a series of PbTiO3/PbZr0.2Ti0.8O3 superlattices on SrTiO3 and SrRuO3/SrTiO3 substrates. An a/c polydomain structure was evidenced by reciprocal space mapping and by transmission electron microscopy. Insertion of ultra-thin layers of SrTiO3 at the interfaces between PbTiO3 and PbZr0.2Ti0.8O3 layers has inhibited this polydomain formation. A strong decrease in the tetragonality indicates clearly that the polarization state in these superlattices has changed due to the insertion of the SrTiO3 layers. A purely elastic mechanism does not seem to explain the determined structural parameters.