A5036632584- Ferroelectric and Piezoelectric Materials
- Quantum Dots Synthesis And Properties
- Silicon Nanostructures and Photoluminescence
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- ZnO doping and properties
- Semiconductor materials and interfaces
- Acoustic Wave Resonator Technologies
- Advanced Memory and Neural Computing
- Multiferroics and related materials
- Copper-based nanomaterials and applications
- Nanowire Synthesis and Applications
- Ferroelectric and Negative Capacitance Devices
- Gas Sensing Nanomaterials and Sensors
- Gold and Silver Nanoparticles Synthesis and Applications
- Glass properties and applications
- Semiconductor Quantum Structures and Devices
- Microwave Dielectric Ceramics Synthesis
- Perovskite Materials and Applications
- Magnetic and transport properties of perovskites and related materials
- Advanced Semiconductor Detectors and Materials
- Luminescence Properties of Advanced Materials
- Nonlinear Optical Materials Studies
- Thin-Film Transistor Technologies
University of Minho
2015-2024
University of Bucharest
2023
Regional Government of Madeira
2023
Centro de Estudos em Psicologia da Saúde
2023
Câmara Municipal de Almada
2023
Agencia Regional da Energia e Ambiente da Regiao Autonoma da Madeira
2023
Universidade Federal de Pernambuco
2022
Universidade Estadual do Ceará
2022
Sociedade Portuguesa de Cardiologia
2022
Clinical Academic Center of Braga
2020
Abstract Herein, the effect of insertion a thin dielectric HfO 2 :Al O 3 (HAO) layer at different positions in Pt/0.5Ba(Zr 0.2 Ti 0.8 )O –0.5(Ba 0.7 Ca 0.3 )TiO (BCZT)/Au structure on energy storage performance capacitors is investigated. A high achieved through HAO between BCZT and Au layers. The causes depolarization field which results linearity hysteresis loop with low dissipation. Pt/BCZT/HAO/Au show an impressive density 99.8 J cm −3 efficiency 71.0%, applied electric 750 kV −1 ....
Self-powered photodetectors are advantageous over conventional because they can have outstanding performance in the absence of an external power source, which is important for a range applications, including Internet Things. Current research has demonstrated different types self-powered utilizing photovoltaic effect, pyroelectric piezoelectric and synergic effects, such as piezo-phototronic pyro-phototronic effects. Such effects been standard semiconductors, hybrid inorganic-organic halide...
A new approach for the stabilization of ferroelectric orthorhombic ZrO2 films is demonstrated through nanosecond laser annealing (NLA) as-deposited Si/SiOx /W(14 nm)/ZrO2 (8 nm)/W(22 nm), grown by ion beam sputtering at low temperatures. The NLA process optimization guided COMSOL multiphysics simulations. annealed under optimized conditions reveal presence phase, as confirmed X-ray diffraction, electron backscatter and transmission microscopy. Macroscopic polarization-electric field...
A modified model of metal-semiconductor contacts is applied to analyze the capacitance-voltage and current-voltage characteristics metal-ferroelectric-metal structures. The ferroelectric polarization considered as a sheet surface charge situated at fixed distance from interface. presumable high concentration structural defects acting active electric traps taken into account by introducing deep acceptorlike level. on set metal-Pb(Zr,Ti)O3-metal samples with different Zr∕Ti ratios, deposited...
Coupling together the pyroelectric effect, photovoltaic effect and plasmonic is a novel method to significantly enhance performance of self-powered photodetectors in visible region.
Asymmetric metal–ferroelectric–metal (MFM) structures were manufactured by sol–gel deposition of a lead zirconate-titanate (PZT with Zr/Ti ratio 65/35) film on Pt-coated Si, Au top electrode. The average remnant polarization 9 μC/cm2 and the coercive field 39 kV/cm obtained from hysteresis loop measurements. A detailed analysis polarization–electric (P–E), capacitance–voltage (C–V), current–voltage (I–V) measurement results allowed us to estimate near-electrode space-charge region thickness...
This paper reports on the development and spectral analysis of Sm3+ (1.0%) Dy3+ doped lithium-boro-tellurite glasses. A bright orange (4G5/2-->6H7/2) along with a red (4G5/2-->6H9/2) yellow (4G5/2-->6H5/2) emission transition have been measured from glass. Both blue (4F9/2-->6H15/2) (4F9/2-->6H13/2) bands obtained From decay profiles, lifetimes emissions glass (4G5/2-->6H5/2, 7/2, 9/2 11/2) at an excitation 401 nm found to be in range 0.47-0.81 ms, respect (4F9/2-->6H15/2 13/2), 450 nm, are...
High energy density of 54.3 J cm<sup>−3</sup> with an efficiency 51.3% was obtained for the ZrO<sub>2</sub> film capacitors 2 nm-thick HAO insert layer.
Inorganic ferroelectric thin films and their composites with unique physical properties have motivated extensive research work achieved substantial advances for flexible electronic energy device applications.
Self-powered photodetectors (PDs) have been recognized as one of the developing trends next-generation optoelectronic devices. Herein, it is shown that by introducing a thin layer SnO film between Si substrate and ZnO film, self-powered photodetector Al/Si/SnO/ZnO/ITO exhibits stable uniform violet sensing ability with high photoresponsivity fast response. The introduces built-in electrostatic field to highly enhance photocurrent over 1000%. By analyzing energy diagrams p-n junction,...
Ancient ceramic wall tiles, called “azulejo”, firstly used on Portuguese churches, monasteries and palaces (15-18th century) have progressively been in particular houses till the last century. These tiles its use huge decorative panels can be considered as a precious but fragile cultural heritage from Brazil to India, several countries influenced by culture. Morphologically, these are composed porous clay-based body, terracotta, covered protective glassy phase, glaze. As artistic paintings,...
This work reports the impact of ZnO layer thickness on optical and resistive switching behavior BaTiO3/ZnO heterostructures grown by pulsed laser deposition. The interface polarization coupling becomes more efficient causes a remarkable change in heterostructure properties with decrease thickness. 25 nm displays enhanced characteristics ratio ≈106 good stability low high resistance states. Moreover, photoluminescence spectrum exhibits two additional blue emissions when is ≤50 their mechanism...
Abstract An enhanced resistive switching (RS) effect is observed in Pt/BaTiO 3 (BTO)/ITO ferroelectric structures when a thin HfO 2 :Al O (HAO) dielectric layer inserted between Pt and BTO. The P-E hysteresis loops reveal the nature of both Pt/BTO/ITO Pt/HAO/BTO/ITO structures. relation RS polarization reversal investigated at various temperatures structure. It found that induces barrier variation Pt/HAO/BTO interface causes RS, which suppressed Curie temperature ( T c = 140 °C)....
A new approach for epitaxial stabilisation of ferroelectric orthorhombic (o-) ZrO2 films with negative piezoelectric coefficient in ∼ 8nm thick grown by ion-beam sputtering is demonstrated. Films on (011)-Nb:SrTiO3 gave the oriented o-phase, as confirmed transmission electron microscopy and backscatter diffraction mapping, grazing incidence x-ray Raman spectroscopy. Scanning probe techniques macroscopic polarization-electric field hysteresis loops show behavior, saturation polarization ∼14.3...
For the first time highly efficient photon energy up-conversion (anti-Stokes photoluminescence) has been observed in colloids of CdTe nanocrystals (NCs) and CdSe NCs covered by ZnS shell. The maximum magnitude up-converted blue shift ΔEUCmax = 335 meV was obtained for CdSe/ZnS under excitation a low-power He–Ne laser. efficiency conversion estimated to be about ηmax 2.7 × 10—2 % at room temperature. intensity anti-Stokes photoluminescence increases with temperature shows linear dependence on...
Abstract Calcium-doped ZnO (CZO) nanopowders were synthesized using the sol–gel method. The structural characteristics investigated by X-ray diffraction (XRD) and analysis reveals that our samples are crystalized in a wurtzite hexagonal structure. morphological properties chemical composition of nanoparticles studied transmission electron microscopy (TEM), scanning (SEM), energy-dispersive spectroscopy (EDX). obtained powders stoichiometric with crystallites nanometric scale aggregated...
Non-resonant Raman spectroscopy studies of a set CdS films annealed at different temperatures were performed and showed direct correlation between the width peak produced by CdS-like optical phonons crystalline quality semiconductor phase probed x-ray diffraction (XRD) transmission electron microscopy (TEM). In order to decribe lineshape model proposed Trallero-Giner et al (1998 Phys. Rev. B 57 4664) was used, which considers confined in small spheres with size distribution. The is shown...