0000000000038457
AUTHOR
Giuseppe Greco
showing 30 related works from this author
Effect of high temperature annealing (T > 1650 °C) on the morphological and electrical properties of p-type implanted 4H-SiC layers
2019
This work reports on the effect of high temperature annealing on the electrical properties of p-type implanted 4H-SiC. Ion implantations of Aluminum (Al) at different energies (30-200 keV) were carried out to achieve 300 nm thick acceptor box profiles with a concentration of about 10(20) at/cm(3). The implanted samples were annealed at high temperatures (1675-1825 degrees C). Morphological analyses of the annealed samples revealed only a slight increase of the surface roughness RMS up to 1775 degrees C, while this increase becomes more significant at 1825 degrees C (RMS = 1.2 nm). Room temperature Hall measurements resulted in a hole concentration in the range 0.65-1.34 x 10(18)/cm(3) and m…
Management of Early Glottic Cancer Treated by CO2 Laser According to Surgical-Margin Status: A Systematic Review of the Literature
2021
Abstract Introduction Transoral laser microsurgery (TLM) is the treatment of choice for Tis-T2 squamous cell glottic carcinomas due to its advantages compared with open surgery and radiotherapy. However, the CO2 laser beam causes changes and damage on the specimens, making the histological assessment of resection margins, the gold standard for confirming radical tumor resection, sometimes difficult. Objective To assess the different ways to manage patients depending on the status of the histopathological margin according to recent studies to detect the most commonly shared therapeutic strategy. Data Synthesis We analyzed the literature available on the PubMed and Web of Science databases, i…
Nanoscale structural and electrical properties of graphene grown on AlGaN by catalyst-free chemical vapor deposition
2020
The integration of graphene (Gr) with nitride semiconductors is highly interesting for applications in high-power/high-frequency electronics and optoelectronics. In this work, we demonstrated the direct growth of Gr on Al0.5Ga0.5N/sapphire templates by propane (C3H8) chemical vapor deposition (CVD) at temperature of 1350{\deg}C. After optimization of the C3H8 flow rate, a uniform and conformal Gr coverage was achieved, which proved beneficial to prevent degradation of AlGaN morphology. X-ray photoemission spectroscopy (XPS) revealed Ga loss and partial oxidation of Al in the near-surface AlGaN region. Such chemical modification of a 2 nm thick AlGaN surface region was confirmed by cross-sec…
Barrier inhomogeneity in vertical Schottky diodes on free standing gallium nitride
2019
Abstract In this paper, the electrical behavior of a Ni/Au Schottky barrier on free standing GaN has been studied employing a variety of techniques and correlated with the material and interface quality. The temperature dependence of the ideality factor (n) and of the Schottky barrier height (ΦB) revealed a spatial inhomogeneity of the barrier. This behavior has been described by means of the Tung's model on inhomogeneous Schottky barriers. The origin of the barrier inhomogeneity can be likely associated to the surface quality of the GaN epilayer or to microstructure of the Ni/GaN interface.
Metal/Semiconductor Barrier Properties of Non-Recessed Ti/Al/Ti and Ta/Al/Ta Ohmic Contacts on AlGaN/GaN Heterostructures
2019
This paper compares the metal/semiconductor barrier height properties of non-recessed Ti/Al/Ti and Ta/Al/Ta contacts on AlGaN/GaN heterostructures. Both contacts exhibited a rectifying behavior after deposition and after annealing at temperatures up to 550 °
Effect of opuntia ficus-indica mucilage edible coating on quality, nutraceutical, and sensorial parameters of minimally processed cactus pear fruits
2021
Cactus pear (Opuntia ficus-indica (L.) Mill.) is a non-climacteric fruit with a relatively short postharvest life span, being very sensitive to water loss, darkening and decay. Cactus pear is a spiny fruit, and the presence of glochids limits fruit consumption and diffusion
Functional Near Infrared Spectroscopy System Validation for Simultaneous EEG-FNIRS Measurements
2019
Functional near-infrared spectroscopy (fNIRS) applied to brain monitoring has been gaining increasing relevance in the last years due to its not invasive nature and the capability to work in combination with other well–known techniques such as the EEG. The possible use cases span from neural-rehabilitation to early diagnosis of some neural diseases. In this work a wireline FPGA–based fNIRS system, that use SiPM sensors and dual-wavelength LED sources, has been designed and validated to work with a commercial EEG machine without reciprocal interference.
Temperature and time dependent electron trapping in Al2O3 thin films onto AlGaN/GaN heterostructures
2022
In this article, the charge trapping phenomena in Al2O3 thin films grown by atomic layer deposition (ALD) on AlGaN/GaN heterostructures have been studied by time-dependent capacitance–voltage (C-V) measurements as a function of temperature. In particular, monitoring the transient of the capacitance enabled us to estimate the maximum depth of the insulating layer interested by the negative charge trapping effect under our bias stress conditions and to determine a charge traps density in the bulk Al2O3 in the order of 3 × 1019 cm−3. A temperature dependent C-V analysis up to 150 °C demonstrated the presence of two competitive mechanisms that rule the electron capture and emission in the Al2O3…
Behavior Modification of Nanostructured PbO2 Electrodes in Lead Acid Batteries Changing Electrolyte Concentration and Separator
2019
Currently, lead acid battery is extensively investigated owing to its prevalent use as a startinglighting and ignition device. An essential role for electrochemical reactions is played by the surface area available for conversion reactions and a possible approach is the use of nanostructured electrodes. In this work, lead dioxide nanostructured electrodes were tested in order to investigate the dependence of the charge and discharge behaviour on some parameters such as electrolyte concentration, and a new type of thin separator. In this last case, it is possible to reduce the size of the cell by using a very thin separator comparable to the nanostructured electrode thickness. Besides, a low…
Exploring FPGA Based Lock-in Techniques for Brain Monitoring Applications
2017
Functional Near Infrared Spectroscopy (fNIRS) systems for e-health applications usually suffer of poor signal detection mainly due to a low end-to-end signal to noise ratio of the electronics chain. Lock-In Amplifiers (LIA) historically represent a powerful technique helping to improve performances in such circumstances. In this work it has been designed and implemented a digital LIA system, based on a Zynq® Field Programmable Gate Array (FPGA), trying to explore if this technique might improve fNIRS system performances. More broadly, FPGA based solution flexibility has been investigated, with particular emphasis applied to digital filter parameters, needed in the digital LIA, and i…
Fiberless, Multi-Channel fNIRS-EEG System Based on Silicon Photomultipliers: Towards Sensitive and Ecological Mapping of Brain Activity and Neurovasc…
2020
Portable neuroimaging technologies can be employed for long-term monitoring of neurophysiological and neuropathological states. Functional Near-Infrared Spectroscopy (fNIRS) and Electroencephalography (EEG) are highly suited for such a purpose. Their multimodal integration allows the evaluation of hemodynamic and electrical brain activity together with neurovascular coupling. An innovative fNIRS-EEG system is here presented. The system integrated a novel continuous-wave fNIRS component and a modified commercial EEG device. fNIRS probing relied on fiberless technology based on light emitting diodes and silicon photomultipliers (SiPMs). SiPMs are sensitive semiconductor detectors, whose large…
Ambipolar MoS2 Transistors by Nanoscale Tailoring of Schottky Barrier Using Oxygen Plasma Functionalization
2017
One of the main challenges to exploit molybdenum disulfide (MoS2) potentialities for the next-generation complementary metal oxide semiconductor (CMOS) technology is the realization of p-type or ambipolar field-effect transistors (FETs). Hole transport in MoS2 FETs is typically hampered by the high Schottky barrier height (SBH) for holes at source/drain contacts, due to the Fermi level pinning close to the conduction band. In this work, we show that the SBH of multilayer MoS2 surface can be tailored at nanoscale using soft O-2 plasma treatments. The morphological, chemical, and electrical modifications of MoS2 surface under different plasma conditions were investigated by several microscopi…
The Impact of Narrow-band Imaging on the Pre- and Intra- operative Assessments of Neoplastic and Preneoplastic Laryngeal Lesions. A Systematic Review
2020
Abstract Introduction Narrow-band imaging is an endoscopic diagnostic tool that, focusing on superficial vascular changes, is useful to detect suspicious laryngeal lesions, enabling their complete excision with safe and tailored resection margins. Objectives To analyze the applications and benefits of narrow-band imaging in detecting premalignant and malignant laryngeal lesions through a comparison with white-light endoscopy. Data Synthesis A literature search was performed in the PubMed, Scopus and Web of Science databases using strict keywords. Then, two authors independently analyzed the articles, read the titles and abstracts, and read completely only the relevant studies according to c…
Exploring FPGA‐Based Lock‐In Techniques for Brain Monitoring Applications
2017
Functional near‐infrared spectroscopy (fNIRS) systems for e‐health applications usually suffer from poor signal detection, mainly due to a low end‐to‐end signal‐to‐noise ratio of the electronics chain. Lock‐in amplifiers (LIA) historically represent a powerful technique helping to improve performance in such circumstances. In this work a digital LIA system, based on a Zynq® field programmable gate array (FPGA) has been designed and implemented, in an attempt to explore if this technique might improve fNIRS system performance. More broadly, FPGA‐based solution flexibility has been investigated, with particular emphasis applied to digital filter parameters, needed in the digital LIA, and its …
Highly Homogeneous 2D/3D Heterojunction Diodes by Pulsed Laser Deposition of MoS2 on Ion Implantation Doped 4H-SiC
2022
In this paper, 2D/3D heterojunction diodes have been fabricated by pulsed laser deposition (PLD) of MoS2 on 4H-SiC(0001) surfaces with different doping levels, i.e., n− epitaxial doping (≈1016 cm−3) and n+ ion implantation doping (>1019 cm−3). After assessing the excellent thickness uniformity (≈3L-MoS2) and conformal coverage of the PLD-grown films by Raman mapping and transmission electron microscopy, the current injection across the heterojunctions is investigated by temperature-dependent current–voltage characterization of the diodes and by nanoscale current mapping with conductive atomic force microscopy. A wide tunability of the transport properties is shown by the SiC surface dopi…
Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS2 Obtained by MoO3 Sulfurization
2022
In this paper, we report a multiscale investigation of the compositional, morphological, structural, electrical, and optical emission properties of 2H-MoS2 obtained by sulfurization at 800 °C of very thin MoO3 films (with thickness ranging from ~2.8 nm to ~4.2 nm) on a SiO2/Si substrate. XPS analyses confirmed that the sulfurization was very effective in the reduction of the oxide to MoS2, with only a small percentage of residual MoO3 present in the final film. High-resolution TEM/STEM analyses revealed the formation of few (i.e., 2–3 layers) of MoS2 nearly aligned with the SiO2 surface in the case of the thinnest (~2.8 nm) MoO3 film, whereas multilayers of MoS2 partially standing up with r…
Impact of contact resistance on the electrical properties of MoS2 transistors at practical operating temperatures
2017
Molybdenum disulphide (MoS2) is currently regarded as a promising material for the next generation of electronic and optoelectronic devices. However, several issues need to be addressed to fully exploit its potential for field effect transistor (FET) applications. In this context, the contact resistance, RC, associated with the Schottky barrier between source/drain metals and MoS2 currently represents one of the main limiting factors for suitable device performance. Furthermore, to gain a deeper understanding of MoS2 FETs under practical operating conditions, it is necessary to investigate the temperature dependence of the main electrical parameters, such as the field effect mobility (μ) an…
Mucilage-Based and Calcium Ascorbate Edible Coatings Improve Postharvest Quality and Storability of Minimally Processed Cactus Pear Fruit Stored unde…
2022
The minimally processed fruit and vegetable industry showed rapid growth worldwide, primarily due to the increasing consumer need for ready-to-eat fresh products characterized by high nutritional, sensory and healthy value. The postharvest life of peeled cactus pear fruits is relatively short, due to the processing operations that affect fruit integrity and cause metabolic disfunctions, as well as pulp browning, microbial growth, loss of firmness, off-flavor development, and nutraceutical value loss. In this study, we investigated the effects of mucilage-based (OFI) and calcium ascorbate edible coating on minimally processed cactus pear summer-ripening fruit, cold stored under passive atmos…
Ohmic contacts on n-type and p-type cubic silicon carbide (3C-SiC) grown on silicon
2019
This paper is a report on Ohmic contacts on n-type and p-type type cubic silicon carbide (3C-SiC) layers grown on silicon substrates. In particular, the morphological, electrical and structural properties of annealed Ni and Ti/Al/Ni contacts has been studied employing several characterization techniques. Ni films annealed at 950 degrees C form Ohmic contacts on moderately n-type doped 3C-SiC (N-D similar to 1 x 10(17) cm(-3)), with a specific contact resistance of 3.7 x 10(-3) Omega cm(2). The main phase formed upon annealing in this contact was nickel silicide (Ni2Si), with randomly dispersed carbon in the reacted layer. In the case of a p-type 3C-SiC with a high doping level (N-A similar …
Influence of Cactus Pear Mucilage-Based Edible Coating on Marketability and Edibility Parameters of Minimally Processed Loquat Fruits
2022
Loquat fruit, popular all over the world for its mild, subacid, and sweet taste, has been classified as a non-climacteric fruit with a very short postharvest life. The fruit decays quickly after harvest, and losses in titratable acidity, taste, and juiciness, and internal browning occurs rapidly during shelf life. The aim of our study was to assess the effects of cactus pear mucilage-based coating on quality, nutraceutical value, microbiological growth, and sensorial parameters of minimally processed white-flesh Martorana and orange-red-flesh Gigante Rossa loquat fruits during cold storage. The effect of mucilage edible coating on the postharvest life, qualitative attributes, and nutraceuti…
Hemangiopericytoma: A cause of recurrent epistaxis
2020
Hemangiopericytoma is a soft tissue tumor with histological variability and unpredictable clinical and biological behavior. this disease is uncommon in the head and neck and the growth pattern is unspecific; thus, diagnosis is often made by exclusion. A 43-year-old woman presented with a story of recurrent epistaxis associated to a growing mass in the paranasal sinus and a paraneoplastic syndrome. the imaging revealed an hypervascular tumor in the right nasal cavity and obliteration of all the ipsilateral sinus cavities. after biopsy the lesion was removed with resolution of epistaxis and paraneoplastic syndrome. There has been no evidence of disease recurrence in 3 years of follow-up. Our …
FPGA based digital lock-in amplifier for fNIRS systems
2018
Lock-In Amplifiers (LIA) represent a powerful technique helping to improve signals detectability when low signal to noise ratios are experienced. Continuous Wave functional Near Infrared Spectroscopy (CW-fNIRS) systems for e-health applications usually suffer of poor detection due to the presence of strong attenuations of the optical recovering path and therefore small signals are severely dipped in a high noise floor. In this work a digital LIA system, implemented on a Zynq® Field Programmable Gate Array (FPGA), has been designed and tested to verify the quality of the developed solution, when applied in fNIRS systems. Experimental results have shown the goodness of the proposed solutions.
Wearable, Fiber-less, Multi-Channel System for Continuous Wave Functional Near Infrared Spectroscopy Based on Silicon Photomultipliers Detectors and …
2019
Development and in-vivo validation of a Continuous Wave (CW) functional Near Infrared Spectroscopy (fNIRS) system is presented. The system is wearable, fiber-less, multi-channel (16×16, 256 channels) and expandable and it relies on silicon photomultipliers (SiPMs) for light detection. SiPMs are inexpensive, low voltage and resilient semiconductor light detectors, whose performances are analogous to photomultiplier tubes (PMTs). The advantage of SiPMs with respect to PMTs is that they allow direct contact with the scalp and avoidance of optical fibers. In fact, the coupling of SiPMs and light emitting diodes (LEDs) allows the transfer of the analog signals to and from the scalp through thin …
Impact of resection margin status and revision transoral laser microsurgery in early glottic cancer: analysis of organ preservation and local disease…
2022
Abstract Introduction Transoral laser microsurgery represents the treatment of choice for early glottic cancer. Its use and effectiveness are mainly related to laryngeal exposure and deep extension of tumor. Histopathologic assessment of surgical margin presents a main issue about transoral laser microsurgery and complete oncological excision. Objective The aim was to analyze the impact of revision surgery on organ preservation and local disease control in patients with early glottic cancer treated by transoral laser microsurgery. Methods We carried out a retrospective study on a cohort of 153 patients with early glottic cancer (Tis, T1, T2) treated by transoral laser microsurgery. Resectio…
Modification of the sheet resistance under Ti/Al/Ni/Au Ohmic contacts on AlGaN/GaN heterostructures
2018
This paper reports on the modification of the sheet resistance under Ti/Al/Ni/Au Ohmic contacts on AlGaN/GaN heterostructures, studied by means of Transmission Line Model (TLM) structures, morphological and structural analyses, as well as computer simulations. In particular, the contacts exhibited an Ohmic behaviour after annealing at 800 degrees C, with a specific contact resistance rho(c) = (2.4 +/- 0.2) x 10(-5) Omega cm(2), which was associated to morphological and structural changes of both the metal layer and the interface. Interestingly, TLM analyses gave a value of the sheet resistance under the contact (R-SK = 26.1 +/- 5.0 Omega/rectangle) significantly lower than that measured out…
Ohmic Contacts on p-Type Al-Implanted 4H-SiC Layers after Different Post-Implantation Annealings
2019
This paper reports on the electrical activation and Ohmic contact properties on p-type Al-implanted silicon carbide (4H-SiC). In particular, the contacts were formed on 4H-SiC-implanted layers, subjected to three different post-implantation annealing processes, at 1675 °
Melanotic Oncocytic Metaplasia of the Nasopharynx: An Unusual Case Report
2021
Introduction: Melanotic oncocytic metaplasia of the nasopharynx is an uncommon disease, usually asymptomatic, that could be misdiagnosed for melanoma, because of its macroscopic features. For this reason, is necessary to know it thoroughly and to take it into account in the differential diagnosis. Case Report: A 69-year-old Italian woman presented to our Otorhinolaryngology Clinic with a 1-month history of sore throat. She has been a smoker for several years. During the nasopharyngoscopic examination, grey-brown, irregular and slightly elevated lesions, measuring few millimetres, were found near the right Eustachian tube opening. The preliminary diagnostic hypothesis was malignant disease…
Quality of Life with Voice Prosthesis after Total Laryngectomy.
2021
Introduction: The loss of voice after total laryngectomy is one of the main impairments in personal and social life. In order to prevent potential psycho-social consequences in the patient and his family, the restoration of phonatory function is the main objective of post-laryngectomy rehabilitation. The aim of this study was to assess quality of life in patients who received prosthetic voice after total laryngectomy. Materials and Methods: Over a one-year period, 51 patients with voice prostheses after total laryngectomy were recruited. 32 patients (62.74%) were administered radiation therapy and 9 patients (17.64%) underwent to surgical reconstruction with flaps. Each patient was administ…
Carotid Sinus Syndrome Secondary to Laryngocele: A Case Report
2021
Introduction: Carotid sinus syndrome (CSS) is a hypersensitivity of the carotid sinus manifested by atrioventricular sinus bradycardia or decreased arterial pressure of at least 50 mmHg. Triggering factors can be neck movements, shaving of the beard or too-tight collars. CSS can be rarely caused by the presence of malignant or benign masses in the head and neck area. Case Report: A 49 years-old white woman with a laterocervical mass presented recurrent episodes of sinus bradycardia related to head’s rotation. Neck CT scan revealed a right piolaryngocele and internal left laryngocele. Episodes of bradycardia were disappeared after endolaryngeal carbon dioxide laser assisted marsupialization.…
Impact of resection margin status and revision transoral laser microsurgery in early glottic cancer: analysis of organ preservation and local disease…
2022
Abstract Introduction Transoral laser microsurgery represents the treatment of choice for early glottic cancer. Its use and effectiveness are mainly related to laryngeal exposure and deep extension of tumor. Histopathologic assessment of surgical margin presents a main issue about transoral laser microsurgery and complete oncological excision. Objective The aim was to analyze the impact of revision surgery on organ preservation and local disease control in patients with early glottic cancer treated by transoral laser microsurgery. Methods We carried out a retrospective study on a cohort of 153 patients with early glottic cancer (Tis, T1, T2) treated by transoral laser microsurgery. Resectio…