Search results for "beam [charged particle]"
showing 10 items of 686 documents
Design, near-field characterization, and modeling of 45 circle surface-plasmon Bragg mirrors
2006
The development of surface plasmon polariton (SPP) optical elements is mandatory in order to achieve surface plasmon based photonics. A current approach to reach this goal is to take advantage of the interaction of SPP with defects and design elements obtained by the micro- or nano-structuration of the metal film. In this work, we have performed a detailed study of the performance and behavior of SPP-Bragg mirrors, designed for 45\ifmmode^\circ\else\textdegree\fi{} incidence, based on this approach. Mirrors consisting of gratings of both metal ridges on the metal surface and grooves engraved in the metal, fabricated by means of electron beam lithography and focused ion beam, have been consi…
Growth, structural and optical properties of AlGaN nanowires in the whole composition range.
2013
International audience; We report on the growth of AlxGa1-xN nanowires by plasma-assisted molecular beam epitaxy for x in the 0.3-0.8 range. Based on a combination of macro- and micro-photoluminescence, Raman spectroscopy, x-ray diffraction and scanning electron microscopy experiments, it is shown that the structural and optical properties of AlGaN NWs are governed by the presence of compositional fluctuations associated with strongly localized electronic states. A growth model is proposed, which suggests that, depending on growth temperature and metal adatom density, macroscopic composition fluctuations are mostly of kinetic origin and are directly related to the nucleation of the AlGaN na…
Potential of amorphous Mo–Si–N films for nanoelectronic applications
2003
The properties of amorphous metallic molybdenum–silicon–nitrogen (Mo–Si–N) films were characterised for use in nanoelectronic applications. The films were deposited by co-sputtering of molybdenum and silicon targets in a gas mixture of argon and nitrogen. The atomic composition, microstructure and surface roughness were studied by RBS, TEM and AFM analyses, respectively. The electrical properties were investigated in the temperature range 80 mK to 300 K. No transition into a superconductive state was observed. Nanoscale wires were fabricated using electron beam lithography with their properties measured as a function of temperature.
Thickness-dependent properties of ultrathin bismuth and antimony chalcogenide films formed by physical vapor deposition and their application in ther…
2021
This work was supported by the European Regional Development Fund (ERDF) project No 1.1.1.1/16/A/257. J. A. acknowledges the ERDF project No. 1.1.1.2/1/16/037. Institute of Solid State Physics, University of Latvia, Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017 TeamingPhase2 under grant agreement No. 739508, project CAMART2 . The raw/processed data required to reproduce these findings cannot be shared at this time as the data also form a part of an ongoing study.
High Performance Solar Blind Detectors based on AlGaN grown by MBE and MOCVD
2004
ABSTRACTSolar blind detectors based on AlGaN grown by Molecular Beam Epitaxy and Metal Organic Vapor Phase Epitaxy have been fabricated and characterized. Metal Semiconductor Metal (MSM) detectors and vertical Schottky detectors have been realized, with a design that allows back side illumination. The growth was optimized in order to improve the layer quality, avoid crack formation, and provide the best detector performance. The technological process was also optimized in order to reduce the dark currents and improve the spectral rejection ratio, which is a key factor for solar blind detection. As a result, a rejection ratio of 5 decades between the UV (below 300 nm) and 400 nm, and a steep…
Epitaxial thin films of intermetallic compounds
2002
Publisher Summary The potential of epitaxial thin films of intermetallic compounds in basic and applied research is emerging. Although the growth of semiconductor heterostructures and compounds based on molecular beam epitaxy (MBE) and related methods has come through a 30-year history of ongoing refinement and sophistication, still much has to be learned concerning the growth and characterization of even moderately complex metallic thin film structures. MBE represents a well-defined crystallization technique based on the reactions among molecular or atomic beams of the constituent elements on a substrate or template at elevated temperatures in an ultrahigh vacuum (UHV) environment. Owing t…
Controlling the carrier-envelope phase of few-cycle focused laser beams with a dispersive beam expander
2008
We report on a procedure to focalize few-cycle laser pulses in dispersive media with controlled waveform. Stationarity of the carrier-envelope phase for extended depth of focus is attained by shaping the spatial dispersion of the ultrashort beam. An adjustable group velocity is locally tuned in order to match a prescribed phase velocity at focus. A hybrid diffractive-refractive lens system is proposed to drive the wavefield to an immersion microscope objective under convenient broadband modulation. Numerical simulations demonstrate robustness over positioning of this dispersive beam expander.
Different strategies towards the deterministic coupling of a single Quantum Dot to a photonic crystal cavity mode
2011
In this work we show two different procedures of fabrication aiming towards the systematic positioning of single InAs quantum dots (QDs) coupled to a GaAs photonic crystal (PC) microcavity. The two approaches are based on the molecular beam epitaxial (MBE) growth of site-controlled QDs (SCQDs) on pre-patterned structures. The PC microcavity (PCM) is introduced previous or after the growth, on each case. We demonstrate the InAs SCQD nucleation on pre-patterned PCMs and a method to perform the QD nucleation respect to an etched ruler that is used to position the PC structure after growth. For both types of structures, we have carried out microphotoluminescence (µPL) spectroscopy experiments a…
Holographic recording in amorphous chalcogenide semiconductor thin films
2003
Abstract A detailed study of the amorphous As–S–Se and As2S3 films as recording media for optical holography and electron beam lithography is presented. The results of R&D on resist based on the amorphous As–S–Se thin films for manufacturing of embossed holographic labels are discussed. The holographic recording of transmission and Bragg gratings was studied.
<title>Amorphous chalcogenide semiconductor resists for holography and electron-beam lithography</title>
2001
The photo- and electron beam induced changes in solubility of amorphous chalcogenide semiconductor As-S-Se and As2S3 thin films have been studied. The possibilities of practical application of these materials as resists for the production of relief holograms and holographic optical elements are discussed. It is shown that the self-enhancement phenomenon of holographic recording in amorphous chalcogenide semiconductor films by light or thermal treatment can be used to increase the diffraction efficiency of the holograms.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.