Papers by Vincenzo Augelli
ACS Applied Materials & Interfaces, 2012
The optical properties of zinc (hydr)oxide and its porous composites with 2% and 5% graphite oxid... more The optical properties of zinc (hydr)oxide and its porous composites with 2% and 5% graphite oxide (GO), thus forming ZnGO-2 and ZnGO-5, are investigated using reflectance spectroscopy and two-photon fluorescence (TPF) imaging. The bandgap energies for the ZnOH 2 , ZnGO-2, and ZnGO-5 samples are determined to be in the range between 2.88 and 3.60 eV. The size of light-emitting regions (∼from 4.5 to 45 μm) and pore size (∼from 20 to 255 μm) are measured using the TPF imaging technique.
Physica Scripta, 1988
Photoconductivity measurements as a function of the temperature and light intensity were carried ... more Photoconductivity measurements as a function of the temperature and light intensity were carried out on samples of hydrogenated and halogenated silicon films. The samples were deposited by r.f. glow discharge starting from a mixture of silicon tetrachloride and hydrogen. Experimental data were analysed by using a theoretical model which assumes a density of states distribution having two exponential band tails
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1997
... changes the working wavelength and the switching threshold of the device due to the diamagnet... more ... changes the working wavelength and the switching threshold of the device due to the diamagnetic blue-shift of the exciton ground-level energy and ... M. Di Dio, M. Lomascolo, A. Passaseo, C. Gerardi, A. Quirini, PV Giugno, M. De Vittorio, D. Greco, AL Convertino, L. Vasanelli, R ...
MRS Proceedings, 2012
ABSTRACTThe integration of biopolymers into hybrid electronics is one of the up to date issues in... more ABSTRACTThe integration of biopolymers into hybrid electronics is one of the up to date issues in view of the achievement of fully bio-compatible devices. Among ‘hot topics’ in bio-polymer research, synthetic melanin or, briefly, “melanin”, has been recently recognized as a quite intriguing macromolecule thanks to its multifunctional optoelectronic properties. To date, melanin transport properties have been mainly enlightened on pellets, while optical absorption and conductivity properties have been investigated on melanin layers deposited on quartz and indium tin oxide/glass. The unavailability of suitable procedures to improve or promote adequate self assembling of melanin layer deposition onto substrate of interest in organic and solid state electronics (hybrid) like silicon substrates, prevent interesting studies on such structures. The reason stems basically on the difference between the hydrophilic nature of the melanin and the hydrophobic one of the supports (mostly of silico...
Materials Science Forum, 1996
ABSTRACT Films of ZnOCdTe have been deposited by reactive sputtering using as starting materials ... more ABSTRACT Films of ZnOCdTe have been deposited by reactive sputtering using as starting materials CdTe crystalline powder spreaded on a ZnO target and covering a fraction of the target area. The I composition of the sputtering gas was, respectively, 100% Ar, 10% H-2/Ar, 20% H-2/Ar. Films deposited in different conditions have been characterized from a structural, optical and electrical point of view. Three different series of samples have been investigated with different percentage of CdTe (10%, 30% and 60% of the target area covered by CdTe powder) and different composition of the sputtering gas. X-ray diffraction evidences a polycrystalline structure for samples deposited with 10% and 30% of CdTe and an amorphous structure for samples deposited with 60% of CdTe. Optical transmission measurements evidence a dependence of absorption coefficient on the percentage of hydrogen in the gas sputtering mixture. Dark conductivity has been measured as a function of temperature in the range 20 K- 300 K. More than one mechanism seem to contribute to electrical transport.
Physical Review B, 1993
Extinction spectra in the range 100-700 nm of sputtered films of hydrogenated amorphous silicon, ... more Extinction spectra in the range 100-700 nm of sputtered films of hydrogenated amorphous silicon, prepared under different conditions, have been obtained at room temperature and at 80 K. The extinction spectra of inhomogeneous samples show the presence of anomalous dips in the range 100-200 nm. These minima can be explained in terms of light interference effects among regions of an
Solid-State Electronics, 2000
We have investigated the photocurrent of GaN and AlGaN epilayers grown on SiC substrates. The pec... more We have investigated the photocurrent of GaN and AlGaN epilayers grown on SiC substrates. The peculiar temperature and intensity dependence of the exciton photocurrent reveal the existence of two dierent carrier localization mechanisms, one due to shallow point defects, which is thermally activated above 150 K and the other due to extended defects, which causes the sublinear intensity dependence of the photocurrent in the whole temperature range comprised between 10 and 300 K. Comparison with temperature dependent photoluminescence experiments suggests that Ga-vacancies can be responsible for the observed localization at point defects, whereas the high-density of native extended defects (as inferred by Rutherford back-scattering experiments) is responsible for the intensity dependence of the photocurrent. However they are localized close to the interface and do not propagate across the bulk of the layer resulting in a good quality of the sample.
Journal of Non-Crystalline Solids, 2009
Natural and synthetic melanin have been investigated by means of optical, electrical and photoele... more Natural and synthetic melanin have been investigated by means of optical, electrical and photoelectronic measurements. Optical measurements evidence absorption curves which allow to estimate optical gap for synthetic melanin, by using Tauc's method. Dark conductivity and photoconductivity measurements were performed as a function of temperature and for different duration of thermal treatments. It has been evidenced that both quantities are thermally activated and thermal treatments play a very important role as far as gap states are concerned.
Natural Hazards and Earth System Science, 2008
Dante e la sua visione della scienza, 2022
Dante, diminuitivo di Durante, nacque a Firenze tra maggio e giugno del 1265. I suoi genitori fur... more Dante, diminuitivo di Durante, nacque a Firenze tra maggio e giugno del 1265. I suoi genitori furono Alaghiero degli Alaghieri e Bella, nobili fiorentini decaduti, di parte guelfa. Tra i loro antenati si annovera Cacciaguida, cavaliere di Corrado III, morto in Terra Santa nel corso della seconda Crociata. Gli scritti su Dante costituiscono un insieme difficilmente numerabile e tantissime sono anche le biografie. Ci limitiamo qui a richiamare il percorso culturale che si presume Dante abbia fatto e che giustifica la sua vasta cultura emergente dalla sue opere e, in particolare, dalla Divina Commedia. Nel collegio di Santa Croce, sotto la guida di un "maestro Romano", apprende la grammatica (il latino) all'età di circa 7 anni. A 18 anni muore il padre e con i redditi di famiglia può dedicarsi allo studio e alla poesia in particolare. Fu uno degli autori più importanti della corrente letteraria 'Dolce stil novo' il cui precursore fu Guido Guinizzelli. Nel 1287 frequenta, probabilmente, le scuole di retorica e di diritto a Bologna. Suo maestro di retorica fu Brunetto Latini. Dopo la morte di Beatrice (1290) a soli 25 anni, inizia lo studio della filosofia e nel 1295 s'iscrive all'Arte dei Medici e Speziali che gli consente di partecipare alla vita pubblica e nel 1300 viene eletto Priore di Firenze, carica della durata di due mesi. Se si considerano le varie opere scritte da Dante (Divina Commedia, la Vita Nuova (1292-93), le Rime, il Convivio, scritto in volgare tra il 1304 e il 1307, per rendere accessibili anche al pubblico più vasto temi scientifici e filosofici, il trattato latino De vulgari eloquentia, il Monarchia, trattato politico in tre libri, le due Egloghe latine composte tra il 1319 e il 1320, le tredici Epistole latine, scritte tra il 1304 e il 1319, la Quaestio de acqua et de terra, tesi filosofica letta e discussa a Verona nel 1320) è praticamente certo che egli aveva studiato le discipline del trivium (grammatica, la retorica e la dialettica) e del quadrivium (geometria, l'aritmetica, l'astronomia e la musica). Al di sopra delle sette arti si ergeva la filosofia naturale che comprendeva anche la fisica. Come vedremo in quanto segue, Dante fa riferimento nella Divina Commedia a varie questioni di aritmetica, geometria, logica formale, fisica, cosmologia, per cui appare evidente la competenza che egli aveva circa i vari argomenti citati. Dante muore nel settembre 1321 a Ravenna. In questo breve saggio discuteremo di quei versi della Divina Commedia che contengono concetti relativi alla matematica, alla fisica, alla logica formale, alla probabilità.
Il Nuovo Cimento D, 1988
ABSTRACT
Seventh E.C. Photovoltaic Solar Energy Conference, 1987
The density of states in the mobility gap of amorphous silicon films has been determined by means... more The density of states in the mobility gap of amorphous silicon films has been determined by means of the field effect measurements.The calculation of the density of states distribution is based on an analytical solution of the Fredholm equation of the first kind,relating the induced space charge density and the density of states.
Il Nuovo Cimento D, 1989
ABSTRACT
Physical Review B - PHYS REV B, 1978
A model is presented by which the various transport parameters (ambipolar diffusion length, hole ... more A model is presented by which the various transport parameters (ambipolar diffusion length, hole and electron lifetimes, and surface recombination velocities) are obtained directly by fitting the experimental photomagnetoelectric and photoconductivity spectral distributions. The model improves the one introduced by Gärtner, since it allows for different hole and electron lifetimes and for anisotropy of mobilities. An experimental application to n-GaSe is presented, and the results are discussed and compared with previous ones.
Thin Solid Films, 1982
ABSTRACT
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Papers by Vincenzo Augelli