The realization and performance of vibration energy harvesting MEMS devices based on an epitaxial piezoelectric thin film

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The direct photo-electrochemical conversion of water and carbon dioxide (CO2) into valuable fuels and chemical commodities using concentrated solar light represents a promising route for sustainable fuel and material production. This thesis presents the design, characterization, operation, and optimization of an integrated photo-electrochemical (P-EC) device for CO2 reduction to carbon monoxide (CO) and ethylene (C2H4) with possible subsequent one-step thermochemical conversion into aviation fuels. The func

Charge transport and extraction in polycrystalline perovskite films are often hindered by inefficient carrier transfer across grain domain boundaries (GDBs). Herein, we present a universal post-treatment strategy leveraging supramolecular crown ether-assisted slow release and precise delivery of Rb⁺ cations to GDBs, achieving in-situ GDB bridging. The solid-state nuclear magnetic resonance (NMR), transmission electron microscopic (TEM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses

This work reports on irradiations made on silicon bulk-acoustic wave resonators. The resonators were based on a tuning fork geometry and actuated by a piezoelectric aluminum nitride layer. They had a resonance frequency of 150 kHz and a quality factor of about 20000 under vacuum. The susceptibility of the devices to radiation induced degradation was investigated using 60Co γ-rays and 50 MeV protons with space-relevant doses of up to 170 krad. The performance of the devices after irradiation indicated a high

© the Partner Organisations 2014. Mesoporous TiO2 microbead films have been investigated as working electrodes for solid state dye sensitized solar cells and 3.5% efficiency was achieved for 4 micrometer thick films under 1 sun illumination. Compared to conventional mesoporous solar cells, microbead films have higher porosity, increased open circuit voltage, lower fill factor and current density, faster transport time and lower electron lifetime. Cross sectional scanning electron microscopy results show tha

We study the plasmonic and the non-plasmonic regimes of operation of a thin-film amorphous-silicon solar cell. By rigorous calculation, we discuss the impact of the cell geometry on the nature of its optical resonances.

Areas/Paper type – 08. Integration of renewable energy in the built environment, Methodology Background – Today’s simulation technology in engineering and architecture are very impressive. As a result technology developers have a good idea of the resulting energy consumption of a building. They even have an idea of the distribution of the possible output. At CISBAT 2011, some authors presented innovative technologies with detailed impact on energy consumption (energy quantity, type, time of consumption) but

It was noticed long time ago that the dielectric permittivity of BaTiO3 single crystals in the rhombohedral phase varies from observation to observation, but the microstructure mechanism behind this phenomenon remained unclear. We show that the variations in susceptibility can be related to the variable domain structure introduced by different pre-treatments at higher temperatures: Electrical depoling at room temperature leads to nano-sized domains and ultrahigh susceptibility in rhombohedral phase, whereas

We investigated the composition and optical properties of GaInAsN/GaAs single quantum wells (QWs) grown on vicinal-(001) GaAs substrates using metallorganic vapor phase epitaxy with modulated nitrogen-precursor flux. A significant enhancement in N incorporation and photoluminescence efficiency is achieved with such optimized QW structures. Possible mechanisms of the observed increase in N uptake and reduction in defect density, related to the substrate vicinality, are discussed.

We report on the temperature dependence of ferroelectric metal-oxide-semiconductor (MOS) transistors and explain the observed improved characteristics based on the dielectric response of ferroelectric materials close to the Curie temperature. The hysteretic current-voltage static characteristics of a fully depleted silicon-on-insulator transistor, with 40 nm vinylidene fluoride trifluorethylene, and 10 nm SiO2 gate stack, are measured from 300 to 400 K. In contrast with conventional MOS field effect transis

We investigate n-i-p/n-i-p micromorph tandem cells deposited at process temperature below 200°C in order to be compatible with low Tg (

We investigate the dielectric permittivity of SiO2 on Si(100) substrates using a first-principles approach. It is shown that both the static and high-frequency dielectric constants of the oxide overlayer increase when the oxide thickness is reduced. This behavior of the overlayer is found to be well reproduced by a classical two-layer model in which the pure oxide and the suboxide layer are treated as distinct dielectrics. Implications for interfaces between silicon and high-k gate oxides are discussed. (C)

Novel, highly sensitive piezoelectric acoustic sensors based on partially unclamped Pb(Zr-x, Ti1-x)O-3 (PZT) coated cantilever and bridge have been fabricated by silicon micromachining. High sensitivity at low frequencies (5-100 Hz) has been achieved by patterning very narrow slits (3 to 5 mum) around the structures. A typical response of 100 mV Pa-1 and a noise equivalent pressure of 1.6 mPa Hz(1/2) at 20 Hz have been measured using a 10 pF charge amplifier. Stress compensation, dry etching and integration

A fast modulator for a dynamic supply linear RF amplifier has been integrated in a 0.35-μm CMOS technology. The use of this modulator with an external linear power amplifier (PA) allows to maintain its efficiency at a higher level than it would with the same PA supplied at constant voltage. The modulator is designed to follow rapid envelope variations at high efficiency without compromising the RF PA linearity.

The printing of lead zirconate titanate (PZT, Pb(Zr,Ti)O-3) piezoelectric thick films on silicon substrates is being studied for potential use as microactuators, microsensors, and micro.. transducers. A fundamental challenge in the fabrication of useful PZT thick-film devices on silicon is to sinter the PZT to high density at sufficiently low temperature to avoid mechanical or chemical degradation of the silicon substrate. The goal of the present study is to develop and implement suitable electrodes and PZT

The fluctuating behavior of a Sulzer Metco F4 de plasma gun has been investigated by simultaneous measurement of the:time dependencies of the are voltage and of images from the nozzle interior. An end-on imaging arrangement using a mirror and a mask in the optical path from the are to the camera allows visualization of the anodic are attachment by strongly attenuating the bright emission from the are column, With the torch operating in the restrike mode, sequences of images have been acquired in synchroniza

The effective piezoelectric coefficient e(31) has been measured on sol-gel processed Pb(ZrxTi1-x)O-3 thin films with Zr concentrations ranging from 45 to 60%. The largest value was observed at 45% Zr, although dielectric constant and effective d(33) peak at 53% Zr. The findings suggest that the optimal composition for microactuators and sensors is less than or equal to 45% Zr, i.e., in the tetragonal part of the phase diagram.

The non-linear dielectric properties of single crystals of PbMg1/3Nb2/3O3 relaxer ferroelectric were investigated experimentally by using measurements of the dielectric permittivity of this material as a function of the DC bias and the AC driving fields. The results were analyzed using four models of the dielectric response of relaxors currently discussed in the literature, It was shown that among them only one model was consistent with the experimental data. This provides strong evidence that the mechanism

In this paper the simple accelerometers based on PZT thin films were developed and characterized. The functions of seismic mass and spring are given by a boss loaded cantilever structure. The strain of the cantilever is detected by a Pb(Zr,Ti)O-3 thin film. A 2 mm long and 0.8 mm wide cantilever yielded a response of 0.6 mV/g In the frequency interval between I and 600 Hz. With Delta f = 600Hz a limit of about 1mg* at 1Hz, and less above this frequency, was observed. The response predicted by the analytical

Pb(Zr1–xTix)O3 thin films (x = 0.55 and 0.85) were prepared on fine grained, polished ZrO2 ceramic substrates by a sol-gel method. The high thermal expansion of ZrO2 relative to Si allows the preparation of thicker PZT films with reduced thermal stress. For the x = 0.85 films, this reduction of thermal stress gives a preference of (001) over (100) oriented domains. For x = 0.55 films, square P–E hysteresis loops were obtained with: Pr = 36 µC/Cm2, and Ec = 45 kV/cm, at a field of 160 kV/cm. Pyroelectric fig

The realization and performance of vibration energy harvesting MEMS devices based on an epitaxial piezoelectric thin film

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Photo-Electrochemical Devices: Design, Characterization, and Operation

In-situ boundary bridging unlocks multi-grain-domain carrier diffusion in polycrystalline metal halide perovskites

Evaluation of silicon tuning-fork resonators under space-relevant radiation conditions

Mesoporous TiO2 microbead electrodes for solid state dye-sensitized solar cells

Light-trapping in the near field: the case for plasmonic thin-film solar cells

INDEX OF ENERGY PRESENT VALUE: Assessment tool for energy savings and distributed energy production

Unusual dielectric behavior and domain structure in rhombohedral phase of BaTiO3 single crystals

High-quality 1.3 lm-wavelength GaInAsN/GaAs quantum wells grown by metalorganic vapor phase epitaxy on vicinal substrates

Ferroelectric transistors with improved characteristics at high temperature

ASYMMETRIC INTERMEDIATE REFLECTOR FOR N-I-P MULTI-JUNNCTION THIN FILM SILICON SOLAR CELLS

Dielectric effect of a thin SiO2 interlayer at the interface between silicon and high-k oxides

Piezoelectric Pb(Zr-x,Ti1-x)O-3 thin film cantilever and bridge acoustic sensors for miniaturized photoacoustic gas detectors

A fast Modulator for dynamic supply linear RF power amplifier

Processing and properties of screen-printed lead zirconate titanate piezoelectric thick films on electroded silicon

Time-resolved imaging of anodic arc root behavior during fluctuations of a dc plasma spraying torch

In-plane piezoelectric coefficient of PZT thin films as a function of composition

Mechanism of polarization response and dielectric non-linearity of PbMg1/3Nb2/3O3 relaxor ferroelectric

Fabrication and characterization of micromachined accelerometers based on PZT thin films

Sol-gel deposition of PZT thin films on ceramic ZrO2 substrates