A5011442328- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Electronic and Structural Properties of Oxides
- Ferroelectric and Negative Capacitance Devices
- Semiconductor materials and devices
- Microwave Dielectric Ceramics Synthesis
- ZnO doping and properties
- Gas Sensing Nanomaterials and Sensors
- MXene and MAX Phase Materials
- Cellular and Composite Structures
- Analytical Chemistry and Sensors
- Acoustic Wave Resonator Technologies
- Magnetic and transport properties of perovskites and related materials
- Glass properties and applications
- Advanced Photocatalysis Techniques
- Catalytic Processes in Materials Science
- Mesoporous Materials and Catalysis
- Luminescence Properties of Advanced Materials
- High-Temperature Coating Behaviors
- Conducting polymers and applications
- Transition Metal Oxide Nanomaterials
- Copper-based nanomaterials and applications
- nanoparticles nucleation surface interactions
- Advanced materials and composites
- Advanced Sensor and Energy Harvesting Materials
National Institute of Materials Physics
2014-2023
University of Pitesti
2019-2022
Brunel University of London
2021-2022
University of Bucharest
2013-2015
Electrode interface is a key element in controlling the macroscopic electrical properties of ferroelectric capacitors based on thin films. In case epitaxial ferroelectrics, electrode essential leakage current and polarization switching, two important elements read/write processes nonvolatile memories. However, relation between bound charges electronic interfaces not yet well understood. Here we show that are height potential barriers at Pb(Zr,Ti)O3 BaTiO3 The results suggest set to value...
Zirconia- and hafnia-based thin films have attracted tremendous attention in the past decade because of their unexpected ferroelectric behavior at nanoscale, which enables downscaling devices. The present work reports an unprecedented rhombohedral phase ZrO2 that can be achieved grown directly on (111)-Nb:SrTiO3 substrates by ion-beam sputtering. Structural characterizations reveal (111)-oriented under epitaxial compressive strain exhibiting switchable polarization about 20.2 μC/cm2 with a...
The compensation of the depolarization field in ferroelectric layers requires presence a suitable amount charges able to follow any variation polarization. These can be free carriers or charged defects located material coming from electrodes. Here we show that self-doping phenomenon occurs epitaxial, tetragonal films Pb(Zr0.2Ti0.8)O3, consisting generation point (vacancies) acting as donors/acceptors. are introducing partly compensate occurring film. It is found concentration introduced by...
Plasma assisted atomic oxygen deposition was used to grow polycrystalline ferroelectric Hf1-xZrxO2 (x = 0.5–0.7) on technologically important (100) Germanium substrates showing sharp crystalline interfaces free of interfacial amorphous layers and strong evidence for the presence a predominately orthorhombic phase. The electrical properties, evaluated using metal-ferroelectric-semiconductor (MFS) capacitors, show symmetric robust hysteresis with weak or no wake-up effects. MFS capacitors x...
Abstract The work describes the development of a flexible, hydrogel embedded pH-sensor that can be integrated in inexpensive wearable and non-invasive devices at epidermal level for electrochemical quantification H + ions sweat. Such device useful swift, real time diagnosis monitoring specific conditions. sensors’ working electrodes are flexible poly(methyl methacrylate) electrospun fibers coated with thin gold layer electrochemically functionalized nanostructured palladium/palladium oxide....
In the last decade orthorhombic hafnia and zirconia films have attracted tremendous attention arising from discovery of ferroelectricity at nanoscale. However, an initial wake-up pre-cycling is usually needed to achieve a ferroelectric behaviour in these films. Recently, different strategies, such as microstructure tailoring, defect, bulk interface engineering, doping, NH3 plasma treatment epitaxial growth, been employed obtain free this work we review recent developments obtaining polar...
We present a hard and soft x-ray photoelectron spectroscopy study of the interface chemistry in pristine TiN/La-doped Hf0.5Zr0.5O2/TiN capacitors. An oxynitride phase (∼1.3 nm) is formed at top interface, while TiO2−δ was detected near bottom interface. The oxygen vacancy (VO) concentration higher than film due to scavenging by electrode. VO also found increase from ∼1.5 1.9 × 1020 cm−3 when increasing La doping 1.7 2.7 mol. %. Two dopants are compensated formation one positively charged VO.
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.
We report on the fabrication of magnetite/salicylic acid/silica shell/antibiotics (Fe(3)O(4)/SA/SiO(2)/ATB) thin films by matrix-assisted pulsed laser evaporation (MAPLE) to inert substrates. Fe(3)O(4)-based powder have been synthesized and investigated XRD TEM. All were studied FTIR, SEM in vitro biological assays using Staphylococcus aureus Pseudomonas aeruginosa reference strains, as well eukaryotic HEp-2 cells. The influence obtained nanosystems microbial biofilm development their...
The crystallization of ferroelectric (Hf,Zr)O2 thin films is achieved by playing on the deposition pressure during reactive magnetron sputtering from a Hf/Zr metallic target. Postdeposition annealing was tried at different temperatures in order to optimize quality samples. Structural characterizations are performed transmission electron microscopy (TEM) and electrical carried out. TEM analyses reveal that samples deposited low working show no orthorhombic phase, thus not ferroelectric,...
High aspect ratio CuO nanowires are synthesized by a simple and scalable method, thermal oxidation in air. The structural, morphological, optical, electrical properties of the semiconducting were studied. Au-Ti/CuO nanowire Pt/CuO contacts investigated. A dominant Schottky mechanism was evidenced junction an ohmic behavior observed for junction. nanowire/Pt structure allows measurements intrinsic transport single nanowires. It found that activation describes at higher temperatures, while...
Individually accessible polarization states in multilayer ferroelectric-insulator structures for multi-bit memories.
Epitaxial (1 – x)Ba(Ti0.8Zr0.2)TiO3 x(Ba0.7Ca0.3)TiO3, x = 0.45 (BCZT 45), thin films have been deposited on (001) SrTiO3 (STO) and (001/100) SrLaAlO4 (SLAO) substrates by pulsed laser deposition. X-ray diffraction high-resolution transmission electron microscopy (HRTEM) confirmed the epitaxial growth of films. A high structural quality has evidenced for BCZT/STO Geometric phase analysis (GPA) associated with HRTEM enabled us to obtain microstrain in-plane out-of-plane lattice parameter...
Two ZnO materials of spherical hierarchical morphologies, with hollow (ZnOHS) and solid cores (ZnOSS), were obtained through the hydrolysis zinc acetylacetonate in 1,4-butanediol. The nature defects surface reactivity for two investigated photoluminescence, X-ray photoelectron spectroscopy, electron paramagnetic resonance (EPR) spectroscopy proving coexistence shallow deep and, also, presence polyol byproducts adsorbed on outer layers samples. EPR coupled spin-trapping technique showed that...