José Silva
@cf-um-up.pt
University of Minho
RESEARCH, TEACHING, or OTHER INTERESTS
Condensed Matter Physics, Surfaces, Coatings and Films, Surfaces and Interfaces, Electronic, Optical and Magnetic Materials
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
F.G. Figueiras, J.R.A. Fernandes, J.P.B. Silva, D.O. Alikin, A.C. Lourenço, and P.B. Tavares
Elsevier BV
Ampattu R. Jayakrishnan, Ji S. Kim, Markus Hellenbrand, Luís S. Marques, Judith L. MacManus-Driscoll, and José P. B. Silva
Royal Society of Chemistry (RSC)
Ferroelectric memory devices such as ferroelectric memristors, ferroelectric tunnel junctions, and field-effect transistors are considered among the most promising candidates for neuromorphic computing devices.
Tetiana Zakusylo, Alberto Quintana, Veniero Lenzi, José P. B. Silva, Luís Marques, José Luís Ortolá Yano, Jike Lyu, Jordi Sort, Florencio Sánchez, and Ignasi Fina
Royal Society of Chemistry (RSC)
Magnetoelectric composite multiferroic comprising ferroelectric doped HfO2 and ferromagnetic cobalt coupled films is demonstrated to be a promising candidate for energy efficient memory computing.
Veniero Lenzi, José P. B. Silva, Břetislav Šmíd, Vladimir Matolín, Cosmin M. Istrate, Corneliu Ghica, Judith L. MacManus‐Driscoll, and Luís Marques
Wiley
Rhombohedral phase HfxZr1‐xO2 (HZO, x from 0 to 1) films are promising for achieving robust ferroelectric polarization without the need for an initial wake‐up pre‐cycling, as is normally the case for the more commonly studied orthorhombic phase. However, a large spontaneous polarization observed in rhombohedral films is not fully understood, and there are also large discrepancies between experimental and theoretical predictions. In this work, in rhombohedral ZrO2 thin films, we show that oxygen vacancies are not only a key factor for stabilizing the phase, but they are also a source of ferroelectric polarization in the films. This is shown experimentally through the investigation of the structural properties, chemical composition and the ferroelectric properties of the films before and after an annealing at moderate temperature (400 °C) in an oxygen environment to reduce the VO concentration compared. The experimental work is supported by density functional theory (DFT) calculations which show that the rhombohedral phase is the most stable one in highly oxygen defective ZrO2 films. The DFT calculations also show that VO contribute to the ferroelectric polarization. Our findings reveal the importance of VO for stabilizing rhombohedral ZrO2 thin films with superior ferroelectric properties.
Ampattu Ravikumar Jayakrishnan, José P.B. Silva, Katarzyna Gwozdz, Maria J.M. Gomes, Robert L.Z. Hoye, and Judith L. MacManus-Driscoll
Elsevier BV
Tingfeng Song, Veniero Lenzi, José P. B. Silva, Luís Marques, Ignasi Fina, and Florencio Sánchez
AIP Publishing
Ferroelectric HfO2 films are usually polycrystalline and contain a mixture of polar and nonpolar phases. This challenges the understanding and control of polar phase stabilization and ferroelectric properties. Several factors, such as dopants, oxygen vacancies, or stress, among others, have been investigated and shown to have a crucial role on optimizing the ferroelectric response. Stress generated during deposition or annealing of thin films is a main factor determining the formed crystal phases and influences the lattice strain of the polar orthorhombic phase. It is difficult to discriminate between stress and strain effects on polycrystalline ferroelectric HfO2 films, and the direct impact of orthorhombic lattice strain on ferroelectric polarization has yet to be determined experimentally. Here, we analyze the crystalline phases and lattice strain of several series of doped HfO2 epitaxial films. We conclude that stress has a critical influence on metastable orthorhombic phase stabilization and ferroelectric polarization. On the contrary, the lattice deformation effects are much smaller than those caused by variations in the orthorhombic phase content. The experimental results are confirmed by density functional theory calculations on HfO2 and Hf0.5Zr0.5O2 ferroelectric phases.
José P. B. Silva, Eliana M. F. Vieira, Katarzyna Gwozdz, Nuno E. Silva, Adrian Kaim, Marian C. Istrate, Corneliu Ghica, José H. Correia, Mario Pereira, Luís Marques,et al.
Royal Society of Chemistry (RSC)
Coupling together the pyroelectric effect, the photovoltaic effect and the plasmonic effect is a novel method to significantly enhance the performance of self-powered photodetectors in the visible region.
Majdi Benamara, Pedro Rivero-Antúnez, Hassen Dahman, Manel Essid, Souhir Bouzidi, Marc Debliquy, Driss Lahem, Víctor Morales-Flórez, Luis Esquivias, José P. B. Silva,et al.
Springer Science and Business Media LLC
Kevin V. Alex, José P. B. Silva, Koppole Kamakshi, and Koppole C. Sekhar
Wiley
AbstractThis work shows the fabrication of an efficient ternary heterostructure photocatalyst by integrating ferroelectric BaTiO3 (BTO) as the bottom layer, semiconductor MoO3 as the middle layer and plasmonic silver nanoparticles (Ag NPs) as the top layer, respectively. The BaTiO3/MoO3/Ag (BMA) heterostructure exhibits a higher photodegradation and photocatalytic efficiency of 100% for rhodamine B (RhB) dye under a UV–Visible light illumination of 60 min when compared with its binary heterostructure counterparts BaTiO3/Ag (BA) and MoO3/Ag (MA). The increased photocatalytic activity in BMA heterostructure is attributed to its enhanced interfacial electric field due to the electric double layer formation at BTO‐MoO3 and MoO3‐Ag interfaces. The higher blueshift in the surface plasmon resonance (SPR) peak observed for the BMA heterostructure clearly indicates an increased electron transfer toward the top Ag NPs layer under optical illumination. The higher resistive switching (RS) ratio, the increased difference in voltage minima, and the improved photocurrent generation, as evident from the I–V characteristics, illustrate the enhanced charge carrier generation and separation in BMA heterostructure. A smaller arc radius observed for the Nyquist plot of BMA heterostructure clearly showcases its increased interfacial charge transfer (CT). The CT mechanism and reusability of the BMA heterostructure are also studied.
Eliana M. F. Vieira, José P. B. Silva, Katarzyna Gwozdz, Adrian Kaim, Nuno M. Gomes, Adil Chahboun, Maria J. M. Gomes, and José H. Correia
Wiley
AbstractSelf‐powered photodetectors (PDs) have been recognized as one of the developing trends of next‐generation optoelectronic devices. Herein, it is shown that by introducing a thin layer of SnO film between the Si substrate and the ZnO film, the self‐powered photodetector Al/Si/SnO/ZnO/ITO exhibits a stable and uniform violet sensing ability with high photoresponsivity and fast response. The SnO layer introduces a built‐in electrostatic field to highly enhance the photocurrent by over 1000%. By analyzing energy diagrams of the p‐n junction, the underlying physical mechanism of the self‐powered violet PDs is carefully illustrated. A high photo‐responsivity (R) of 93 mA W−1 accompanied by a detectivity (D*) of 3.1 × 1010 Jones are observed under self‐driven conditions, when the device is exposed to 405 nm excitation laser wavelength, with a laser power density of 36 mW cm−2 and at a chopper frequency of 400 Hz. The Si/SnO/ZnO/ITO device shows an enhancement of 3067% in responsivity when compared to the Al/Si/ZnO/ITO. The photodetector holds an ultra‐fast response of ≈ 2 µs, which is among the best self‐powered photodetectors reported in the literature based on ZnO.
José P. B. Silva, Ruben Alcala, Uygar E. Avci, Nick Barrett, Laura Bégon-Lours, Mattias Borg, Seungyong Byun, Sou-Chi Chang, Sang-Wook Cheong, Duk-Hyun Choe,et al.
AIP Publishing
Ferroelectric hafnium and zirconium oxides have undergone rapid scientific development over the last decade, pushing them to the forefront of ultralow-power electronic systems. Maximizing the potential application in memory devices or supercapacitors of these materials requires a combined effort by the scientific community to address technical limitations, which still hinder their application. Besides their favorable intrinsic material properties, HfO2–ZrO2 materials face challenges regarding their endurance, retention, wake-up effect, and high switching voltages. In this Roadmap, we intend to combine the expertise of chemistry, physics, material, and device engineers from leading experts in the ferroelectrics research community to set the direction of travel for these binary ferroelectric oxides. Here, we present a comprehensive overview of the current state of the art and offer readers an informed perspective of where this field is heading, what challenges need to be addressed, and possible applications and prospects for further development.
Muhassinah Tasneem, Carlos R.P. Monteiro, N.S. Kiran Kumar, J.P.B. Silva, K.C. Sekhar, K. Kamakshi, and M. Pereira
Elsevier BV
N.S. Kiran Kumar, A.R. Jayakrishnan, J.P.B. Silva, and K.C. Sekhar
Elsevier BV
José P. B. Silva, Katarzyna Gwozdz, Luís S. Marques, Mario Pereira, Maria J. M. Gomes, Judith L. MacManus‐Driscoll, and Robert L. Z. Hoye
Wiley
AbstractCoupling together the ferroelectric, pyroelectric, and photovoltaic characteristics within a single material is a novel way to improve the performance of photodetectors. In this work, we take advantage of the triple multifunctionality shown by 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BCZT), as demonstrated in an Al/Si/SiOx/BCZT/ITO thin‐film device. The Si/SiOx acts as an n‐type layer to form a metal–ferroelectric–insulator–semiconductor heterostructure with the BCZT, and with Al and ITO as electrodes. The photo‐response of the device, with excitation from a violet laser (405 nm wavelength), is carefully investigated, and it is shown that the photodetector performance is invariant with the chopper frequency owing to the pyro‐phototronic effect, which corresponds to the coupling together of the pyroelectric and photovoltaic responses. However, the photodetector performance was significantly better than that of the devices operating based only on the pyro‐phototronic effect by a factor of 4, due to the presence of ferroelectricity in the system. Thus, after a poling voltage of −15 V, for a laser power density of 230 mW/cm2 and at a chopper frequency of 400 Hz, optimized responsivity, detectivity, and sensitivity values of 13.1 mA/W, 1.7 × 1010 Jones, and 26.9, respectively, are achieved. Furthermore, ultrafast rise and fall times of 2.4 and 1.5 µs, respectively, are obtained, which are 35,000 and 36,000 times faster rise and fall responses, respectively, than previous reports of devices with the ferro–pyro–phototronic effect. This is understood based on the much faster ferroelectric switching in ferroelectric thin films owing to the predominant 180° domains in a single direction out of plane.
Anna P. S. Crema, Marian C. Istrate, Alexandre Silva, Veniero Lenzi, Leonardo Domingues, Megan O. Hill, Valentin S. Teodorescu, Corneliu Ghica, Maria J. M. Gomes, Mario Pereira,et al.
Wiley
AbstractA new approach for the stabilization of the ferroelectric orthorhombic ZrO2 films is demonstrated through nanosecond laser annealing (NLA) of 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 is guided by COMSOL multiphysics simulations. The films annealed under the optimized conditions reveal the presence of the orthorhombic phase, as confirmed by X‐ray diffraction, electron backscatter diffraction, and transmission electron microscopy. Macroscopic polarization‐electric field hysteresis loops show ferroelectric behavior, with saturation polarization of 12.8 µC cm−2, remnant polarization of 12.7 µC cm−2 and coercive field of 1.2 MV cm−1. The films exhibit a wake‐up effect that is attributed to the migration of point defects, such as oxygen vacancies, and/or a transition from nonferroelectric (monoclinic and tetragonal phase) to the ferroelectric orthorhombic phase. The capacitors demonstrate a stable polarization with an endurance of 6.0 × 105 cycles, demonstrating the potential of the NLA process for the fabrication of ferroelectric memory devices with high polarization, low coercive field, and high cycling stability.
Alexandre Silva, Ignasi Fina, Florencio Sánchez, José P.B. Silva, Luís Marques, and Veniero Lenzi
Elsevier BV
I. H. Mejri, K. Omri, I. Ghiloufi, J. P. B. Silva, M. J. M. Gomes, and L. El Mir
Springer Science and Business Media LLC
AbstractCalcium-doped ZnO (CZO) nanopowders were synthesized using the sol–gel method. The structural characteristics were investigated by X-ray diffraction (XRD) and the analysis reveals that our samples are crystalized in a wurtzite hexagonal structure. The morphological properties and the chemical composition of the nanoparticles were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The obtained powders are stoichiometric with crystallites in a nanometric scale aggregated in micrometric particles. Then, pulsed laser deposition (PLD) technique was used to grow Ca-doped ZnO thin films with different doping concentrations (1, 3, and 5%), on p-type Si substrates. The Ca doping effect on the electrical properties of the CZO films was investigated by current–voltage characteristics. A resistive switching (RS) effect was observed in the ITO/ZnO:Ca/Au structures. The RS behavior is dependent on the Ca doping concentration. The charge transport mechanisms of the devices were studied. In the positive bias voltage region, the transport is dominated by Ohmic and space-charge limited conduction mechanisms under low and high electric fields, respectively.
José P.B. Silva, Marian C. Istrate, Markus Hellenbrand, Atif Jan, Maximilian T. Becker, Joanna Symonowicz, Fábio G. Figueiras, Veniero Lenzi, Megan O. Hill, Corneliu Ghica,et al.
Elsevier BV
A.R. Jayakrishnan, J.P.B. Silva, K. Kamakshi, D. Dastan, V. Annapureddy, M. Pereira, and K.C. Sekhar
Elsevier BV
Adrian KAIM
Wydawnictwo SIGMA-NOT, sp. z.o.o.
. Growing number of photodetectors in use might require sheer amounts of energy to power them and in order to prevent that, studies on self-powered detectors are gaining more popularity. A common approach synergistically couples multiple effects, to combine all of their advantages. In this work we attempt to refine characteristics of a pyro-phototronic device, based on Si/SnO x /ZnO heterojunction, by the introduction of a ferroelectric BCZT (0.5Ba(Zr 0.2 Ti 0.8 )O 3 –0.5(Ba 0.7 Ca 0.3 )TiO 3 ) layer. The influence of the ferroelectric polarization on the performance of the detector is observed, however the enhancement of electric field does not result in improvement of detection parameters.
N.S. Kiran Kumar, A.R. Jayakrishnan, R. Rugmini, J.P.B. Silva, M. Pereira, Sathish Sugumaran, and K.C. Sekhar
Elsevier
S. Angitha, Kevin V. Alex, J.P.B. Silva, K.C. Sekhar, M. Tasneem, and K. Kamakshi
Elsevier
C. González, J.P.B. Silva, A.S. Viana, K. Gwozdz, and O. Conde
Elsevier BV