Search results for "III-V"
showing 9 items of 39 documents
Pagani e cristiani a Sabratha e Leptis Magna tra III e VI secolo d.C. Monumenti e reperti, tradizione e immagini
2012
Contributi sui risultati della ricerca effettuata col Progetto PRIN 2008. Unità di ricerca: Università degli Studi di Palermo, Università degli Studi di Catania, CNR ITABC di Roma
Sabratha. Le trasformazioni dello spazio urbano e lo sviluppo delle aree paleocristiane nelle Regiones III -V: studio preliminare per un GIS archeolo…
2012
Researchers at the University of Palermo, in collaboration with the CNR ITABC for the project PRIN 2008, they have made a preliminary study for an archaeological GIS divided into areas I-XI of Sabratha to gather information on the monuments already studied, or under study, and to promote analysis regarding the reuse of space in the Regiones III-V, after the destruction attributed to the earthquake on 21th of July 365. We present the results of the studies on the Roman Baths of the Regio V and on the Episcopal Complex. The roman baths in the Regio V, insula 1 was born in the second century, with the planning of the Theatre District. Stratigraphic excavations conducted under the mosaics had p…
La decorazione pittorica nei contesti funerari della Sicilia. III-V sec. d.C.
2010
Analisi iconografcia e stilistica degli apparati pittorici presenti nei cimiteri tardoantichi della Sicilia
High accuracy Raman measurements using the Stokes and anti-Stokes lines
1997
We show that by measuring the separation between the Stokes and anti-Stokes peaks excited by two different laser lines we obtain a very precise determination of absolute phonon energies. The method is useful for measuring small changes of these energies with strain, temperature, laser power, etc. It doubles the changes and avoids the necessity of using the reference lines in the Raman spectra. The method can be applied for the determination of phonon deformation potentials, for the characterization of strained heteroepitaxial layers, and for micro-Raman analysis of strain in silicon integrated circuits. We give examples of phonon shifts in Si, Ge, GaAs, InAs, and GaP as a function of applie…
Luminescence properties of III-V multi-junctions solar cells
2012
The recent achievement of multi-junctions solar cells, based on III-V semiconductors, exceeding 43% efficiency, has stimulated a rapid growth of concentration photovoltaic (CPV) technology. The large efficiency of these cells is based on the matching between the semiconductors band gap and the solar spectrum and the capability of working under concentrated illumination, up to ~1000 suns. The research pays, therefore, attention to investigate in detail the mechanisms that affect the conversion efficiency, such as the non radiative losses that increase the cell temperature thus favoring the electron-hole (e-h) recombination. With the aim to clarify the performances of these III-V cells, here …
Effect of carrier transfer on the PL intensity in self-assembled In (Ga) As/GaAs quantum rings
2006
We present results concerning the carrier transfer between In(Ga)As quantum rings in a stacked multilayer structure, which is characterised by a bimodal size distribution. This transfer of carriers explains the observed temperature behaviour of diode lasers based on that kind of stacked layer structures. The inter-ring carrier transfer can be possible by phonon assisted tunnelling from the ground state of the smallring family towards the big-ring family of the bimodal size distribution. This process is thermally activated in the range 40–80 K.
Oxidation-Induced Changes in the ALD-Al2O3/InAs(100) Interface and Control of the Changes for Device Processing
2018
InAs crystals are emerging materials for various devices like radio frequency transistors and infrared sensors. Control of oxidation-induced changes is essential for decreasing amounts of the harmful InAs surface (or interface) defects because it is hard to avoid the energetically favored oxidation of InAs surface parts in device processing. We have characterized atomic-layer-deposition (ALD) grown Al2O3/InAs interfaces, preoxidized differently, with synchrotron hard X-ray photoelectron spectroscopy (HAXPES), low-energy electron diffraction, scanning tunneling microscopy, and time-of-flight elastic recoil detection analysis. The chemical environment and core-level shifts are clarified for w…
Efficiency of concentration photovoltaic cells governed by luminescence processes
2013
The development of multi-junctions III-V semiconductors solar cells, that combine high conversion efficiency (over 40%) and capability of working under high illumination intensity (up to 1000 suns), has stimulated a rapid growth of concentrating photovoltaic (CPV) technology. The performance of these cells is based on the matching between the semiconductors band gap and the solar spectrum so as to optimize the current balancing between the subcells. This requirement is also important in connection with the CPV modules using lenses, mirrors, optical coupling compounds that introduce a wavelength dependent response to the sunlight. Therefore, care must be exercised in designing optimum cells …