Antonio Terrasi | Università di Catania (original) (raw)

Papers by Antonio Terrasi

International Journal of Molecular Sciences

Cu nanoparticles were produced by using solid-state dewetting (dry) of a 1.3 nm Cu layer or laser... more Cu nanoparticles were produced by using solid-state dewetting (dry) of a 1.3 nm Cu layer or laser ablation of a Cu solid target (wet) in acetone and methanol. The morphology and chemical composition of the nanoparticles were investigated as a function of the synthesis methods and their key parameters of the annealing temperature (200–500 °C) and the liquid environment during the ablation. Cu nanoparticles were then embedded in transparent conductive oxide (TCO) films as aluminum-doped zinc oxide (AZO) or zirconium-doped indium oxide (IZrO); the TCObott/Cu nanoparticle/TCOtop structures were synthesized with all combinations of AZO and IZrO as the top and bottom layers. The goal was to achieve a plasmonic and conductive structure for photovoltaic applications via a comparison of the involved methods and all fabricated structures. In particular, solid-state dewetting produced faceted or spherical (depending on the annealing temperature) nanoparticles with an average size below 150 nm ...

Nanomaterials, 2022

Aluminum-doped zinc oxide (AZO) is an electrically conductive and optically transparent material ... more Aluminum-doped zinc oxide (AZO) is an electrically conductive and optically transparent material with many applications in optoelectronics and photovoltaics as well as in the new field of plasmonic metamaterials. Most of its applications contemplate the use of complex and nanosized materials as substrates onto which the AZO forms the coating layer. Its morphological characteristics, especially the conformality and crystallographic structure, are crucial because they affect its opto-electrical response. Nevertheless, it was difficult to find literature data on AZO layers deposited on non-planar structures. We studied the AZO growth on silicon-nanowires (SiNWs) to understand its morphological evolution when it is formed on quasi one-dimensional nanostructures. We deposited by sputtering different AZO thicknesses, leading from nanoclusters until complete incorporation of the SiNWs array was achieved. At the early stages, AZO formed crystalline nano-islands. These small clusters unexpec...

Nanomaterials, 2019

Non-enzymatic electrochemical glucose sensing was obtained by gold nanostructures on graphene pap... more Non-enzymatic electrochemical glucose sensing was obtained by gold nanostructures on graphene paper, produced by laser or thermal dewetting of 1.6 and 8 nm-thick Au layers, respectively. Nanosecond laser annealing produces spherical nanoparticles (AuNPs) through the molten-phase dewetting of the gold layer and simultaneous exfoliation of the graphene paper. The resulting composite electrodes were characterized by X-ray photoelectron spectroscopy, cyclic voltammetry, scanning electron microscopy, micro Raman spectroscopy and Rutherford back-scattering spectrometry. Laser dewetted electrode presents graphene nanoplatelets covered by spherical AuNPs. The sizes of AuNPs are in the range of 10–150 nm. A chemical shift in the XPS Au4f core-level of 0.25–0.3 eV suggests the occurrence of AuNPs oxidation, which are characterized by high stability under the electrochemical test. Thermal dewetting leads to electrodes characterized by faceted not oxidized gold structures. Glucose was detected ...

Solar Energy Materials and Solar Cells, 2019

NATO Science for Peace and Security Series B: Physics and Biophysics, 2012

ABSTRACT Europium-based materials are known for their intense and stable emission in the visible ... more ABSTRACT Europium-based materials are known for their intense and stable emission in the visible region. Moreover Eu is stable in both its divalent and trivalent oxidation states. In particular, emission of Eu2+ is much stronger, being allowed for electric dipole transition rules and is characterized by a broad peak, centered in the wavelength range 400-600 nm, while that of Eu3+ presents several sharp lines at around 600 nm. These peculiar optical properties make Eu-based systems an interesting material for photonic applications. The optical and structural properties of Eu2O3 thin films grown by RF magnetron sputtering on Si substrates have been studied. PL emission has been observed at room temperature and it is strongly dependent on the thermal process. In particular, annealing in O2 atmosphere leads to an enhancement of the Eu3+ emission, while films annealed in N2 ambient exhibit a very intense PL signal due to Eu2+. The chemical and structural characterization of the films, performed by TEM and XPS, reveals that a massive mixing at the Eu2O3-Si interface occurs in N2-annealed samples, leading to the formation of Eu (II) silicates, while in the case of O2-annealed samples we observe the formation of a SiOx layer at the interface, that minimize the diffusion of Si into the Eu2O3 layer.

Nanoscale, 2015

This work elucidates the interplay between quantum confinement and interface effects in the optic... more This work elucidates the interplay between quantum confinement and interface effects in the optical properties of Ge quantum dots, demonstrating that not only size matters at the nanoscale.

Journal of Applied Physics, 2008

The pile-up of arsenic at the Si/SiO2 interface after As implantation and annealing was investiga... more The pile-up of arsenic at the Si/SiO2 interface after As implantation and annealing was investigated by high resolution Z-contrast imaging, electron energy-loss spectroscopy (EELS), grazing incidence x-ray fluorescence spectroscopy (GI-XRF), secondary ion mass spectrometry, x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, as well as Hall mobility and four-point probe resistivity measurements. After properly taking into account their respective artifacts, the results of all methods are compatible with each other, with EELS and GI-XRF combined with etching providing similar spatial resolution on the nanometer scale for the dopant profile. The sheet concentration of the piled-up As at the interface was found to be ∼1×1015 cm−2 for an implanted dose of 1×1016 cm−2 with a maximum concentration of ∼10 at. %. The strain observed in the Z-contrast images also suggests a significant concentration of local distortions within 3 nm from the interface, which, however, do...

Journal of Applied Physics, 2013

Applied Surface Science, 1992

Nanomaterials, 2021

The low efficiency of water electrolysis mostly arises from the thermodynamic uphill oxygen evolu... more The low efficiency of water electrolysis mostly arises from the thermodynamic uphill oxygen evolution reaction. The efficiency can be greatly improved by rationally designing low-cost and efficient oxygen evolution anode materials. Herein, we report the synthesis of Ni–P alloys adopting a facile electroless plating method under mild conditions on nickel substrates. The relationship between the Ni–P properties and catalytic activity allowed us to define the best conditions for the electroless synthesis of highperformance Ni–P catalysts. Indeed, the electrochemical investigations indicated an increased catalytic response by reducing the thickness and Ni/P ratio in the alloy. Furthermore, the Ni–P catalysts with optimized size and composition deposited on Ni foam exposed more active sites for the oxygen evolution reaction, yielding a current density of 10 mA cm−2 at an overpotential as low as 335 mV, exhibiting charge transfer resistances of only a few ohms and a remarkable turnover fr...

ECS Meeting Abstracts, 2010

not Available.

Journal of Applied Physics, 2015

The role of the interface potential on the effective mass of charge carriers is elucidated in thi... more The role of the interface potential on the effective mass of charge carriers is elucidated in this work. We develop a new theoretical formalism using a spatially dependent effective mass that is related to the magnitude of the interface potential. Using this formalism we studied Ge quantum dots (QDs) formed by plasma enhanced chemical vapour deposition (PECVD) and co-sputtering (sputter). These samples allowed us to isolate important consequences arising from differences in the interface potential. We found that for a higher interface potential, as in the case of PECVD QDs, there is a larger reduction in the effective mass, which increases the confinement energy with respect to the sputter sample. We further understood the action of O interface states by comparing our results with Ge QDs grown by molecular beam epitaxy. It is found that the O states can suppress the influence of the interface potential. From our theoretical formalism we determine the length scale over which the interface potential influences the effective mass.

2012 Lester Eastman Conference on High Performance Devices, LEC 2012, 2012

We present on high efficiency metal-insulatorsemiconductor (MIS) photodetectors based on amorphou... more We present on high efficiency metal-insulatorsemiconductor (MIS) photodetectors based on amorphous germanium quantum dots (QDs) embedded in a SiO 2 matrix. High internal quantum efficiencies (IQE) were achieved across a broad wavelength range, with peak value reaching 700% at-10 V applied bias due to high internal photoconductive gain. The transient photoresponse behavior is also studied and it was found that the response time of the photodetector depends on the thickness of the QD layer. We also discuss the conduction mechanism which leads to the high photoconductive gain.

Physical Review B, 2002

In this work the Si self-interstitial-carbon interaction has been experimentally investigated and... more In this work the Si self-interstitial-carbon interaction has been experimentally investigated and modeled. The interactions between self-interstitials, produced by 20-keV silicon implantation, and substitutional carbon in silicon have been studied using a Si 1Ϫy C y layer grown by molecular beam epitaxy ͑MBE͒ and interposed between the near-surface self-interstitial source and a deeper B spike used as a marker for the Si-interstitial concentration. The C atoms, all incorporated in substitutional sites and with a C-dose range of 7ϫ10 12-4 ϫ10 14 atoms/cm 2 , trap the self-interstitials in such a manner that the Si 1Ϫy C y layer behaves as a filtering membrane for the interstitials flowing towards the bulk and, consequently, strongly reduces the boron-enhanced diffusion. This trapping ability is related to the total C dose in the Si 1Ϫy C y membrane. Substitutional carbon atoms interacting with self-interstitials are shown to trap Si interstitials, to be removed from their substitutional sites, and to precipitate into the C-rich region. After precipitation, C atoms are not able to further trap injected self-interstitials, and the interstitials generated in the surface region can freely pass through the C-rich region and produce B-enhanced diffusion. The atomistic mechanism leading to Si-interstitial trapping has been investigated by developing a simulation code describing the migration of injected interstitials. The simulation takes into account the surface recombination, the interstitial diffusion in our MBE-grown material, and C traps. Since the model calculates the amount of interstitials that actually react with C atoms, by a comparison with the experimental data it is possible to derive quantitative indications of the trapping mechanism. It is shown that one Si interstitial is able to deactivate about two C traps by means of interstitial trapping and C clustering reactions. The reaction causing trapping and deactivation is tentatively described.

Thin Solid Films, 2012

ABSTRACT Al-doped ZnO (AZO)/Ag/AZO multilayer coatings (50–70 nm thick) were grown at room temper... more ABSTRACT Al-doped ZnO (AZO)/Ag/AZO multilayer coatings (50–70 nm thick) were grown at room temperature on glass substrates with different silver layer thickness, from 3 to 19 nm, by using radio frequency magnetron sputtering. Thermal stability of the compositional, optical and electrical properties of the AZO/Ag/AZO structures were investigated up to 400 °C and as a function of Ag film thickness. An AZO film as thin as 20 nm is an excellent barrier to Ag diffusion. The inclusion of 9.5 nm thin silver layer within the transparent conductive oxide (TCO) material leads to a maximum enhancement of the electro-optical characteristics. The excellent measured properties of low resistance, high transmittance in the visible spectral range and thermal stability allow these ultra-thin AZO/Ag/AZO structures to compete with the 1 μm thick TCO layer currently used in thin film solar cells.

Thin Solid Films, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights

Thin Solid Films, 2010

In this work we propose an alternative methodology to study B diffusion in crystalline Ge. We enh... more In this work we propose an alternative methodology to study B diffusion in crystalline Ge. We enhance B diffusion by means of passing implants in such a way to increase the point-defects distribution through the sample, well above the equilibrium value. A comparison between B diffusion occurring under implantation with different ions or after post-implantation annealing allowed to discern any

Physica Scripta, 2005

The quantum physics of light is a most fascinating field. Here I present a very personal viewpoin... more The quantum physics of light is a most fascinating field. Here I present a very personal viewpoint, focusing on my own path to quantum entanglement and then on to applications. I have been fascinated by quantum physics ever since I heard about it for the first time in school. The theory struck me immediately for two reasons: (1) its immense mathematical beauty, and (2) the unparalleled precision to which its predictions have been verified again and again. Particularly fascinating for me were the predictions of quantum mechanics for individual particles, individual quantum systems. Surprisingly, the experimental realization of many of these fundamental phenomena has led to novel ideas for applications. Starting from my early experiments with neutrons, I later became interested in quantum entanglement, initially focusing on multi-particle entanglement like GHZ states. This work opened the experimental possibility to do quantum teleportation and quantum hyper-dense coding. The latter became the first entanglement-based quantum experiment breaking a classical limitation. One of the most fascinating phenomena is entanglement swapping, the teleportation of an entangled state. This phenomenon is fundamentally interesting because it can entangle two pairs of particles which do not share any common past. Surprisingly, it also became an important ingredient in a number of applications, including quantum repeaters which will connect future quantum computers with each other. Another application is entanglement-based quantum cryptography where I present some recent long-distance experiments. Entanglement swapping has also been applied in very recent so-called loophole-free tests of Bell's theorem. Within the physics community such loophole-free experiments are perceived as providing nearly definitive proof that local realism is untenable. While, out of principle, local realism can never be excluded entirely, the 2015 achievements narrow down the remaining possibilities for local realistic explanations of the quantum phenomenon of entanglement in a significant way. These experiments may go down in the history books of science. Future experiments will address particularly the freedom-of-choice loophole using cosmic sources of randomness. Such experiments confirm that unconditionally secure quantum cryptography is possible, since quantum cryptography based on Bell's theorem can provide unconditional security. The fact that the experiments were loophole-free proves that an eavesdropper cannot avoid detection in an experiment that correctly follows the protocol. I finally discuss some recent experiments with single-and entangled-photon states in higher dimensions. Such experiments realized quantum entanglement between two photons, each with quantum numbers beyond 10 000 and also simultaneous entanglement of two photons where each carries more than 100 dimensions. Thus they offer the possibility of quantum communication with more than one bit or qubit per photon. The paper concludes discussing Einstein's contributions and viewpoints of quantum mechanics. Even if some of his positions are not supported by recent experiments, he has to be given credit for the fact that his analysis of fundamental issues gave rise to developments which led to a new information technology. Finally, I reflect on some of the lessons learned by the fact that Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.