Letteratura scientifica selezionata sul tema "Hybrid metal/semiconductor light sources"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Hybrid metal/semiconductor light sources".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Articoli di riviste sul tema "Hybrid metal/semiconductor light sources"
1
Yokota, Hiroaki, Atsuhito Fukasawa, Minako Hirano e Toru Ide. "Low-Light Photodetectors for Fluorescence Microscopy". Applied Sciences 11, n. 6 (19 marzo 2021): 2773. http://dx.doi.org/10.3390/app11062773.
Testo completoAbstract (sommario):
Over the years, fluorescence microscopy has evolved and has become a necessary element of life science studies. Microscopy has elucidated biological processes in live cells and organisms, and also enabled tracking of biomolecules in real time. Development of highly sensitive photodetectors and light sources, in addition to the evolution of various illumination methods and fluorophores, has helped microscopy acquire single-molecule fluorescence sensitivity, enabling single-molecule fluorescence imaging and detection. Low-light photodetectors used in microscopy are classified into two categories: point photodetectors and wide-field photodetectors. Although point photodetectors, notably photomultiplier tubes (PMTs), have been commonly used in laser scanning microscopy (LSM) with a confocal illumination setup, wide-field photodetectors, such as electron-multiplying charge-coupled devices (EMCCDs) and scientific complementary metal-oxide-semiconductor (sCMOS) cameras have been used in fluorescence imaging. This review focuses on the former low-light point photodetectors and presents their fluorescence microscopy applications and recent progress. These photodetectors include conventional PMTs, single photon avalanche diodes (SPADs), hybrid photodetectors (HPDs), in addition to newly emerging photodetectors, such as silicon photomultipliers (SiPMs) (also known as multi-pixel photon counters (MPPCs)) and superconducting nanowire single photon detectors (SSPDs). In particular, this review shows distinctive features of HPD and application of HPD to wide-field single-molecule fluorescence detection.
2
Jin, Sangrak, Yale Jeon, Min Soo Jeon, Jongoh Shin, Yoseb Song, Seulgi Kang, Jiyun Bae et al. "Acetogenic bacteria utilize light-driven electrons as an energy source for autotrophic growth". Proceedings of the National Academy of Sciences 118, n. 9 (22 febbraio 2021): e2020552118. http://dx.doi.org/10.1073/pnas.2020552118.
Testo completoAbstract (sommario):
Acetogenic bacteria use cellular redox energy to convert CO2 to acetate using the Wood–Ljungdahl (WL) pathway. Such redox energy can be derived from electrons generated from H2 as well as from inorganic materials, such as photoresponsive semiconductors. We have developed a nanoparticle-microbe hybrid system in which chemically synthesized cadmium sulfide nanoparticles (CdS-NPs) are displayed on the cell surface of the industrial acetogen Clostridium autoethanogenum. The hybrid system converts CO2 into acetate without the need for additional energy sources, such as H2, and uses only light-induced electrons from CdS-NPs. To elucidate the underlying mechanism by which C. autoethanogenum uses electrons generated from external energy sources to reduce CO2, we performed transcriptional analysis. Our results indicate that genes encoding the metal ion or flavin-binding proteins were highly up-regulated under CdS-driven autotrophic conditions along with the activation of genes associated with the WL pathway and energy conservation system. Furthermore, the addition of these cofactors increased the CO2 fixation rate under light-exposure conditions. Our results demonstrate the potential to improve the efficiency of artificial photosynthesis systems based on acetogenic bacteria integrated with photoresponsive nanoparticles.
3
Wei, Hong, e Hongxing Xu. "Nanowire-based plasmonic waveguides and devices for integrated nanophotonic circuits". Nanophotonics 1, n. 2 (1 novembre 2012): 155–69. http://dx.doi.org/10.1515/nanoph-2012-0012.
Testo completoAbstract (sommario):
AbstractThe fast development of plasmonics have greatly advanced our understanding to the abundant phenomena related to surface plamon polaritons (SPPs) and improved our ability to manipulate light at the nanometer scale. With tightly confined local field, SPPs can be transmitted in waveguides of subwavelength dimensions. Nanophotonic circuits built with plasmonic elements can be scaled down to dimensions compatible with semiconductor-based nanoelectronic circuits, which provides a potential solution for the next-generation information technology. Different structures have been explored as plasmonic waveguides for potential integration applications. This review is focused on metallic nanowire waveguides and functional components in nanowire networks. We reviewed recent progress in research about plasmon generation, emission direction and polarization, group velocity, loss and propagation length, and the near-field distribution revealed by quantum dot fluorescence imaging. Electrical generation and detection of SPPs moves towards the building of plasmonic circuits, where bulky external light sources and detectors may be omitted. The coupling between metal nanowires and emitters is important for tailoring light-matter interactions, and for various potential applications. In multi-nanowire structures, plasmon signal control and processing are introduced. The working principles of these nanowire-based devices, which are based on the control to the near field distributions, will become the design rule for nanophotonic circuits with higher complexity for optical signal processing. The recent developments in hybrid photonic-plasmonic waveguides and devices are promising for making devices with unprecedented performance.
4
Oda, Ryosuke, Toshiki Hirogaki, Eiichi Aoyama e Keiji Ogawa. "Hybrid Process of Laser Heat Treatment and Forming of Thin Plate with a Small Power Semiconductor Laser". Advanced Materials Research 1136 (gennaio 2016): 423–29. http://dx.doi.org/10.4028/www.scientific.net/amr.1136.423.
Testo completoAbstract (sommario):
In recent years, the recycling of resources has become important because of the aggravation of global environmental concerns. In light of this, it is necessary to minimize the resource needs of current production systems. This concept is called sustainable development. When this concept is applied to machine tools, the assumption is that small parts should be processed using small machines. Additionally, the diversification of consumer needs and the ephemeralization of product life cycles are progressing in industry. As a result, the overall production system has changed from high-mix low-volume production manufacturing, to variant types in variable quantity. In this background, the cell production system is receiving attention as a production system that can achieve variant types in variable quantity. The cell production system also requires miniaturization and process consolidation of machine tools, which has given rise to the need to consolidate heat treatments, especially as part of the process consolidation of machine tools. Laser beams have proved to be effective heat sources when integrated into heat-treatment processes, such as quenching and tempering on machine tool tables. On the other hand, In the case of the thin plate, it is well known that the deformation of a plate occurs due to laser irradiation, as named a laser forming. The laser forming is also effective to generate the complex shape without a press die set. Thus, we propose that the hybrid process of laser heat treatment and forming of thin plate with a small power semiconductor laser, and demonstrate that the proposed method makes it feasible to generate the hardened sheet metal products with a compact machine tools. Moreover, considering the power consumption in laser quenching and forming process, we investigate an appropriate laser irradiation condition from a view of reducing the environmental burden.
5
Graus, Javier, Carlos Bueno-Alejo e Jose Hueso. "In-Situ Deposition of Plasmonic Gold Nanotriangles and Nanoprisms onto Layered Hydroxides for Full-Range Photocatalytic Response towards the Selective Reduction of p-Nitrophenol". Catalysts 8, n. 9 (27 agosto 2018): 354. http://dx.doi.org/10.3390/catal8090354.
Testo completoAbstract (sommario):
In this work, we present photocatalysis as a greener alternative to conventional catalysis where harsh reaction conditions, temperature and/or pressure are needed. Photodegradation of organic pollutants is a cost-effective, eco-friendly solution for the decontamination of water and air, and is a field that has been continuously growing over the last decade. Plasmonic metal nanoparticles absorb light irradiation that is transferred to the chemical reaction in a different fashion. Furthermore, plasmonic nanostructures can be combined with other materials, such as semiconductors or a basic support, to create hybrid systems capable of overcoming certain challenges that photocatalysis is facing nowadays and to expand the photocatalytic response towards the whole visible-near infrared (Vis-NIR) ranges. The main objective of this work has been to in-situ synthesize plasmonic anisotropic gold nanoparticles onto hydrotalcite (HT) and calcined hydrotalcite (CHT) supports by way of a sequential deposition-reduction (DR) process and to evaluate their efficiency as heterogeneous catalysts towards the selective oxidation of p-nitrophenol (hereafter 4-NP), a well-known model contaminant, either in the absence or the presence of full-range light irradiation sources (LEDs) spanning the whole UV-Vis-NIR range. Special attention has been paid to the optimization of the catalyst preparation parameters, including the pH and the concentration of reducing and stabilizing agents. Interestingly, the use of thermally modified hydrotalcites has enabled a strong metal-support interaction to induce the preferential formation of triangular-shaped Au nanoparticles with ca. 0.8 wt.% loading while increasing the colloidal stability and surface area of the catalyst with respect to the commercial untreated HT supports.
6
Paudel, Hari P., e Michael N. Leuenberger. "Light-Controlled Plasmon Switching Using Hybrid Metal-Semiconductor Nanostructures". Nano Letters 12, n. 6 (30 aprile 2012): 2690–96. http://dx.doi.org/10.1021/nl203990c.
Testo completo
7
Buchal, Ch, e M. Löken. "Silicon-Based Metal-Semiconductor-Metal Detectors". MRS Bulletin 23, n. 4 (aprile 1998): 55–59. http://dx.doi.org/10.1557/s088376940003027x.
Testo completoAbstract (sommario):
Photodetectors must provide fast and efficient conversion of photons to charge carriers. When considering semiconductor light sources, the indirect bandgap of silicon and germanium represents a serious obstacle to radiative electron-hole recombinations. Momentum conservation demands the simultaneous interaction of the electron-hole pair with a momentum-matching phonon. As a consequence, radiative recombinations are five orders of magnitude less probable in Si if compared to a direct semiconductor such as GaAs.Although the absorption of a photon and the generation of an electron-hole pair may be considered as the inverse process to emission, photon absorption within indirect semiconductors is a highly probable process if the photon energy is sufficient to bridge the energy gap in a direct process. The resulting electronhole pair is created in an excited state and relaxes sequentially. The ubiquitous-silicon solar cells operate this way. In the visible spectral range, Si photodetectors have demonstrated fast and efficient performance, being readily adapted for opto electronic applications and being fully compatible to standard-silicon processing schemes.
8
Maeda, Kazuhiko, Keita Sekizawa e Osamu Ishitani. "A polymeric-semiconductor–metal-complex hybrid photocatalyst for visible-light CO2 reduction". Chemical Communications 49, n. 86 (2013): 10127. http://dx.doi.org/10.1039/c3cc45532g.
Testo completo
9
Park, Kyoung-Won, e Alexie M. Kolpak. "Photocatalytic hydrogen evolution activity of Co/CoO hybrid structures: a first-principles study on the Co layer thickness effect". Journal of Materials Chemistry A 7, n. 27 (2019): 16176–89. http://dx.doi.org/10.1039/c9ta04508b.
Testo completoAbstract (sommario):
Interfaces formed at metal/semiconductor hybrid system have the peculiar electronic characteristics depending on the thickness of metal layer. The different characteristics tune light responses of the metallic and semiconducting layers, resulting in various photocatalytic hydrogen evolution activities in the hybrid system.
10
Newaz, A. K. M., W. J. Chang, K. D. Wallace, L. C. Edge, S. A. Wickline, R. Bashir, A. M. Gilbertson, L. F. Cohen e S. A. Solin. "A nanoscale Ti/GaAs metal-semiconductor hybrid sensor for room temperature light detection". Applied Physics Letters 97, n. 8 (23 agosto 2010): 082105. http://dx.doi.org/10.1063/1.3480611.
Testo completoTesi sul tema "Hybrid metal/semiconductor light sources"
1
Toanen, Vincent. "Plasmons Tamm pour la réalisation de nouvelles sources de lumière". Electronic Thesis or Diss., Lyon 1, 2022. http://www.theses.fr/2022LYO10049.
Testo completoAbstract (sommario):
Les plasmons Tamm, ou modes Tamm optiques, sont des modes électromagnétiques présents à l'interface entre un miroir de Bragg (DBR) et une couche métallique. Ces modes présentent un fort intérêt pour la réalisation de nouvelles sources de lumière, notamment grâce à la partie métallique, qui peut d'une part fournir un contrôle et un confinement micrométrique à trois dimensions du mode optique, et d'autre part assurer l'injection d'un courant électrique dans la structure pour y exciter un milieu émetteur. De nombreuses sources de lumière pourraient être réalisées grâce à cette double fonction du métal, comme des sources polarisées intégrées, des générateurs de plasmons de surface ou encore des tableaux de laser adressables à grande échelle. Mon travail de doctorat a consisté à pousser les sources de lumière Tamm vers l'applicatif, en développant leur fonctionnement à température ambiante et en excitation électrique, par opposition aux démonstrations à température cryogénique et en pompage optique effectuées jusqu'alors. Ce développement a été effectué sur des structures semi-conductrices basées sur des alliages ternaires d'AlGaAs, mais est hautement transposable à d'autres familles de matériaux. La première partie de ce travail s'est concentrée sur l'obtention d'un effet laser à température ambiante. Grâce à une amélioration de la structure, consistant à insérer une couche de bas indice entre le DBR semi-conducteur et le métal, les pertes ohmiques dans ce dernier ont été réduites, ce qui a permis d'atteindre le régime laser à température ambiante. Le second volet de cette thèse concerne l'injection électrique des sources de lumière à mode Tamm. Partant d'un DBR dopé, deux procédés de micro-structuration en salle blanche ont été élaborés pour permettre cette injection. Le premier, inspiré de techniques usuelles de micro-fabrication, n'a pas fait ses preuves, en raison de la dégradation de la surface du DBR par certaines étapes classiques de structuration, et de la forte sensibilité du plasmon Tamm à la composition de surface du DBR. Nous avons donc développé une méthode de structuration alternative. Son originalité repose dans la protection permanente de la surface du DBR destinée au contact avec le métal. Cette nouvelle méthode a permis la fabrication des premières diodes électroluminescentes basées sur l'émission dans un mode Tamm. Leur caractérisation a montré la réussite de l'excitation du plasmon Tamm par l'injection électrique des émetteurs à puits quantiques, et prouve la possibilité d'utiliser un unique élément métallique pour confiner le mode optique et injecter les porteurs de charge. Ces résultats constituent une étape importante vers le développement d'une variété de sources de lumière intégrées utilisant les modes TammTamm plasmons, or optical Tamm states, are electromagnetic modes that exist at the interface between a Distributed Bragg Reflector (DBR) and a metallic layer. They are of high interest for the design of new light sources, thanks to the metallic part, which can provide 3D confinement and control of the optical mode but also electrical injection of the structure, in order to excite light emitters. Many light emitting devices could be realised using this dual function, such as integrated polarised light sources, surface plasmon generators or large-scale addressable laser arrays. This PhD work mainly consisted in pushing Tamm light emitting devices towards applicability, with the development of their room-temperature operation and electrical pumping, as opposed to previous demonstrations which were carried out under cryogenic temperature and optical pumping. Semiconducting heterostructures based on ternary alloys of AlGaAs were used for this development, but our results are highly transposable to other families of materials. The first part of this work focused on obtaining a laser effect at room temperature. By improving the structure with the insertion of a low-index layer between the semiconductor DBR and the metal, the ohmic losses in the metal were reduced, thus enabling lasing operation at room temperature. The second part of this work was about achieving the electrical injection of Tamm-based light sources. Starting from a doped DBR with quantum wells, we developed two processes, mostly based on cleanroom microfabrication techniques, to enable electrical injection. The first one, inspired by common microfabrication techniques, has not proved to be successful, due to the degradation of the DBR surface by some standard fabrication steps, and to the strong sensitivity of the Tamm plasmon to the surface composition of the DBR. Therefore, we developed a second method. Its originality lies in a permanent protection of the part of the DBR on which the metallic element will be deposited to form the Tamm mode and inject electrical current. This new method allowed the fabrication of the first light-emitting diodes based on Tamm mode emission. With electro-optical measurements, we demonstrated the excitation of the Tamm plasmon state through electrical pumping of the quantum wells, and proved the possibility to use a single metallic element to confine the optical mode and bring charge carriers into the structure. These results are an important step towards the development of new integrated light emitting devices using Tamm modes
2
Yang, Ying. "Organic semiconductor lasers : compact hybrid light sources and development of applications". Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/2569.
Testo completoAbstract (sommario):
This thesis describes a number of studies on organic semiconductors as laser gain media with the aim of simplifying the excitation scheme and exploring potential applications. A hybrid device taking the advantage of high power inorganic light emitting diodes (LEDs) and low threshold organic distributed feedback lasers is demonstrated to realize a LED pumped organic laser. When the drive current is higher than 152 A, a sharp peak is clearly observed in the laser output spectrum, implying the LED successfully pumps the polymer laser above threshold. This is the first time an incoherent LED has been used as the excitation source for an organic semiconductor laser. A strategy for further improving the performance of the hybrid device is explored with the use of a luminescent concentrator made of a dye doped SU8 film, to intensify the power density from the inorganic LED. The luminescent concentrator is capable of increasing the incident power density by a factor of 9 and reducing the lasing threshold density by 4.5 times. As a preliminary investigation towards mode-locked polymer lasers, the impact of a solid state saturable absorber on a solution based organic semiconductor laser is explored. The dye doped polystyrene thin film saturable absorber exhibits a saturation intensity of a few MW/cm². When it is placed into the laser cavity, a train of short pulses is generated and the underlying mechanism is discussed. Finally, the potential of using organic semiconductor lasers in the detection of nitro-aromatic explosive vapours is studied in distributed feedback polyfluorene lasers. A high sensing efficiency and fast response from the laser prove polyfluorene lasers can be used as disposal and low cost devices in explosive chemosensing.
3
Llopis, Antonio. "Electrostatic Mechanism of Emission Enhancement in Hybrid Metal-semiconductor Light-emitting Heterostructures". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115113/.
Testo completoAbstract (sommario):
III-V nitrides have been put to use in a variety of applications including laser diodes for modern DVD devices and for solid-state white lighting. Plasmonics has come to the foreground over the past decade as a means for increasing the internal quantum efficiency (IQE) of devices through resonant interaction with surface plasmons which exist at metal/dielectric interfaces. Increases in emission intensity of an order of magnitude have been previously reported using silver thin-films on InGaN/GaN MQWs. the dependence on resonant interaction between the plasmons and the light emitter limits the applications of plasmonics for light emission. This dissertation presents a new non-resonant mechanism based on electrostatic interaction of carriers with induced image charges in a nearby metallic nanoparticle. Enhancement similar in strength to that of plasmonics is observed, without the restrictions imposed upon resonant interactions. in this work we demonstrate several key features of this new interaction, including intensity-dependent saturation, increase in the radiative recombination lifetime, and strongly inhomogeneous light emission. We also present a model for the interaction based on the aforementioned image charge interactions. Also discussed are results of work done in the course of this research resulting in the development of a novel technique for strain measurement in light-emitting structures. This technique makes use of a spectral fitting model to extract information about electron-phonon interactions in the sample which can then be related to strain using theoretical modeling.
4
Leipold, David [Verfasser], Erich [Akademischer Betreuer] Runge, Martina [Akademischer Betreuer] Hentschel e Christoph [Akademischer Betreuer] Lienau. "Interaction of Light and Matter in Metal-Semiconductor Hybrid Nanostructures / David Leipold. Gutachter: Martina Hentschel ; Christoph Lienau. Betreuer: Erich Runge". Ilmenau : Universitätsbibliothek Ilmenau, 2015. http://d-nb.info/1075492866/34.
Testo completo
5
Lee, Anna. "Hierarchical Semiconductor, Metal and Hybrid Nanostructures and the Study of their Light-matter Interactions". Thesis, 2012. http://hdl.handle.net/1807/36289.
Testo completoAbstract (sommario):
The work presented in this thesis explores the optical properties of hierarchical structures composed of nanoscale building blocks ranging from metals to semiconductors and composites, organized through bottom-up design methods.
1) By following the dynamic generation of hot-spots in self-assembled chains of gold nanorods (NRs), we have established a direct correlation between ensemble-averaged surface-enhanced Raman scattering (SERS) and extinction properties of these nanoscale chains. Experimental results were supported by comprehensive finite-difference time-domain simulations (FDTD). The relationship established between the structure of nanorod ensembles and their optical properties provides a basis for producing dynamic, solution-based, plasmonic platforms for applications ranging from sensing to nanoelectronics.
2) We report theoretical and experimental analyses of the optical properties of side-by-side assembled gold NRs. Comprehensive FDTD simulations showed a blue shift of the surface plasmon resonance in the side-by-side assembled NR structures and a reduction of electric field intensity as the number of NRs per stack increased. These results were experimentally verified via extinction measurements and ensemble-averaged SERS spectroscopy. The experimental results and electrodynamic simulations were found to be in agreement.
3) The efficacy of hollow core photonic crystal fibers (HCPCF) as a platform for SERS spectroscopy was demonstrated. SERS measurements carried out using this platform showed the capability to monitor minute amounts of ligands on the surface of gold nanoparticles and SERS signals from HCPCF exhibited a 10-fold enhancement. Using the exchange of cetyltrimethylammonium bromide with α-methoxy-ω mercaptopolyethylene glycol on the surface of gold nanorods as an exemplary system, we showed the feasibility of using HCPCF SERS to monitor the change in surface chemistry of NRs.
4) Facile, solution-phase formation of ordered, lamellar quantum dot (QD) arrays exhibiting structural integrity and temporal stability, without the need for chemical crosslinking, was achieved. While micrometers in diameter, they are typically only two to three QD layers thick. These structures are capable of carrying a cargo of water-soluble ions, molecules, metal nanoparticles, or biomolecules. The photoluminescence of the host CdSe QDs were enhanced by the encapsulation of gold nanoparticles within the lamellae, demonstrating the ability to modulate their properties through the cargo they carry.
5) This chapter explores a bottom-up method to produce a metamaterial designed to function as an optical cloak in the visible range. A composite material consisting of an array of silver nanowires (NWs) in a dielectric host has been produced based on the theory of a non-magnetic optical cloak. The required radial array of silver NWs was achieved by electroless deposition of the metal into the channels of a porous alumina structure grown perpendicularly from the curved surface of a micrometer scale aluminum wire. The functionality of the cloak was demonstrated by partial cloaking in the visible range (540 nm).
Libri sul tema "Hybrid metal/semiconductor light sources"
1
Vurgaftman, Igor, Matthew P. Lumb e Jerry R. Meyer. Bands and Photons in III-V Semiconductor Quantum Structures. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198767275.001.0001.
Testo completoAbstract (sommario):
Semiconductor quantum structures are at the core of many photonic devices such as lasers, photodetectors, solar cells etc. To appreciate why they are such a good fit to these devices, we must understand the basic features of their band structure and how they interact with incident light. This book takes the reader from the very basics of III-V semiconductors (some preparation in quantum mechanics and electromagnetism is helpful) and shows how seemingly obscure results such as detailed forms of the Hamiltonian, optical transition strengths, and recombination mechanisms follow. The reader does not need to consult other references to fully understand the material, although a few handpicked sources are listed for those who would like to deepen their knowledge further. Connections to the properties of novel materials such as graphene and transition metal dichalcogenides are pointed out, to help prepare the reader for contributing at the forefront of research. The book also supplies a complete, up-to-date database of the band parameters that enter into the calculations, along with tables of optical constants and interpolation schemes for alloys. From these foundations, the book goes on to derive the characteristics of photonic semiconductor devices (with a focus on the mid-infrared) using the same principles of building all concepts from the ground up, explaining all derivations in detail, giving quantitative examples, and laying out dimensional arguments whenever they can help the reader’s understanding. A substantial fraction of the material in this book has not appeared in print anywhere else, including journal publications.
Capitoli di libri sul tema "Hybrid metal/semiconductor light sources"
1
C. Estrada, Ana, Joana L. Lopes e Tito Trindade. "Nanomaterials of Carbon and Metal Sulfides in Photocatalysis". In Photocatalysts - New Perspectives [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.109658.
Testo completoAbstract (sommario):
Heterogeneous semiconductor photocatalysis has received much interest because of its applications in important global energy and environmental challenges in a cost-effective sustainable way. The photocatalytic efficiency of semiconductor photocatalysts under solar irradiation has been pointed out by difficulties associated with low visible-light absorption range, fast recombination of photogenerated carriers, and low chemical stability in operational conditions. Graphitic materials have attracted great interest due to properties, such as high surface area, mechanical strength, and photochemical stability. Thus, their combination with metal sulfides, has been explored as promising strategies to produce new photocatalysts. These nanocomposites show great potential in photodegradation of contaminants of emerging concern (CEC), which might be detected in water sources, such as traces of Pharmaceutics and pesticides. Here, we briefly review fundamental principles photocatalysis in general, with the focus on the use of carbon-nanomaterials of distinct structural dimensionalities associated with nanocrystalline metal sulfides, envisaging their application as heterogeneous photocatalysts for water remediation. Key aspects concerning the photocatalyst properties, such as light absorption, charge separation and transfer, and stability, are also approached. Graphene and graphene derivatives have demonstrated great potential for increasing photogenerated charge-carrier separation and migration efficiency, as well as in extending the light absorption range and adsorption capacity.
2
Abazari, Reza, Soheila Sanati e Junkuo Gao. "Metal-organic Frameworks and their Derived Structures for Photocatalytic Water Splitting". In Advanced Catalysts Based on Metal-organic Frameworks (Part 2), 1–44. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815136029123010003.
Testo completoAbstract (sommario):
Fossil fuels are non-renewable energy sources and may cause environmental pollution. One of the appropriate solutions is to develop clean and renewable sources of energy as an alternative to fossil fuels. Environmental pollution and lack of renewable energy sources are two significant problems affecting the current life of human society and economic progress. Researchers have addressed semiconductor-oriented heterogeneous photo-electrocatalysis, photocatalysis, and electrocatalysis by the fuel cells to solve these crises. Photocatalytic water splitting is a promising approach in resolving the energy crisis. This process involves harvesting solar light, charge transfer and separation, and evaluation of catalytic reactions of H2 and O2. In this regard, the main challenge is to find an efficient, environmental-friendly, cost-effective, and easily fabricated photocatalyst with high stability and corrosion resistance in different media. Thanks to their tunable structure, structural flexibility, high specific surface area, tunable pores, and unsaturated metal sites, metal-organic frameworks (MOFs) could be an efficient photocatalyst for hydrogen production under UV, NIR, and visible radiation. Therefore, MOFs and MOFs-based compounds are widely utilized as alternatives for expensive commercial catalysts developed based on rare elements such as Pt and Au. They can also be employed as precursors for the synthesis of different types of materials with different structures, sizes, and morphologies. This chapter summarizes MOF-based photocatalysts for the splitting of water are MOFs modification strategies.
Atti di convegni sul tema "Hybrid metal/semiconductor light sources"
1
Hansson, B. A. M., O. Hemberg, G. Johansson, M. Otendal, T. Tuohimaa e P. Takman. "Liquid-metal-jet X-ray tube technology for characterization and metrology in semiconductor applications". In Compact EUV & X-ray Light Sources. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/euvxray.2016.em4a.1.
Testo completo
2
Barbiero, Andrea. "Efficient semiconductor quantum light sources at telecom wavelength based on hybrid circular Bragg gratings (Conference Presentation)". In Quantum Nanophotonic Materials, Devices, and Systems 2022, a cura di Mario Agio, Igor Aharonovich, Cesare Soci e Matthew T. Sheldon. SPIE, 2022. http://dx.doi.org/10.1117/12.2632375.
Testo completo
3
Defreez, R. K., J. Puretz, R. A. Elliott e J. Orloff. "Semiconductor diode lasers formed by micromachining with a focused ion beam". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.wr7.
Testo completoAbstract (sommario):
Currently all commercially available diode lasers are fabricated by cleaving dice from semiconductor wafers with the cleaved facets serving as the cavity mirrors. This practice is well suited to producing discrete devices but severely limits the degree to which these devices can be integrated into large scale monolithic systems. A method of producing laser mirrors, diffraction gratings, and other optical components directly in the surfaces of wafers is needed to integrate light sources with other optical elements and electronic devices. Experiments demonstrating the practicality of micromachining such structures with focused beams of ions from liquid metal sources are described. The micromachining was accomplished with a 20-keV Ga+ ion beam of 0.3-nA current focused to a 250-nm spot. Diode laser output mirrors were formed which show no increase in the lasing threshold and only a 20% decrease in external differential quantum efficiency when compared to cleaved mirror facets. Construction of coupled cavity single and multiple stripe diode lasers with the liquid metal focused-ion-beam micromachining technique is also described. Coupling grooves with submicron widths and depth-to-width aspect ratios of more than 10:1 have been achieved while maintaining the high optical quality of the groove walls.
4
Callender, Claire L., Lucie Robitaille e Julian P. Noad. "Polymer Waveguide Taps for Optical Signal Distribution". In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.md.16.
Testo completoAbstract (sommario):
GaAs optoelectronic integrated circuit (OEIC) technology is having an increasing impact in the areas of communications and signal processing, with applications such as high speed broad-band switching, high-speed interconnects for multiprocessor local area networks (LANs) and optically controlled phased-array antennas. A major component of the production of OEICs is the low cost, robust and reliable integration of optoelectronic devices for generating, amplifying and detecting optical signals. Recently, there has been considerable interest in the integration of photodetectors with optical waveguide circuits. Monolithic integration of metal-semiconductor-metal (MSM) detectors with semiconductor optical waveguides has been achieved by evanescent coupling from a waveguide layer into an absorbing detector layer grown epitaxially on top of the waveguide1,2. In this paper we examine the potential of polyimide waveguides as integrated light distribution systems in monolithic OEICs. Polymer guides can be formed on top of complex semiconductor circuitry by spin coating and photolithography. Polymer waveguides offer the advantages of ease of processing, low cost, and low optical losses. As well, vertical coupling facilitates alignment of light sources and detectors without additional components such as gratings or 45° facets.
5
Kubacki, Frank, Dirk Hauschild, Mikhail Ivanenko, Jens Meinschien, Andreas Bayer e Vitalij Lissotschenko. "Dynamic Thermal Thin Film Processing of Large Areas With High Power Laser Sources". In ASME 2009 International Manufacturing Science and Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/msec2009-84105.
Testo completoAbstract (sommario):
High power laser sources are used in various production tools for cutting, welding and hardening of metal parts and patterning, annealing and lithography of flat panel displays, solar cells and microelectronic devices. Beside the right choice of the laser source suitable high performance optical beam delivery and shaping systems are needed for generating the appropriate beam profile and intensity distribution are of high importance for the right processing speed, quality and yield. In addition to the typical laser processes with circular beam shapes LIMO has developed laser sources with line shaped beams for large area processing for e.g. crystallization and tempering of conducting and semi-conducting films on glass for FPD, PV and thermal processing of semiconductor wafer, coated float glass and sheet metal. Due to the high power density of several 100kW/cm2 and line length up to several hundred millimetres a treatment capacity of several m2 per minute and processing speeds up to 1 m/s can be achieved per laser head with typical scan & repeat processes. The use of multiple laser heads in one machine scales the productivity to the individual needs. The high scanning speed together with line widths of 0,01mm to 0,1mm is the basis for heating only a few microns of the surfaces layers and no costly cooling time is needed like with regular heating technologies. With this controlled surface heating even more sensitive materials can be processes like inks on polymers and paper for RFIDs, printed solar absorbers and coatings. For industrial applications equally important is an adequate understanding of the physics of the light-matter interaction behind the process. In advance simulations of the tool performance can minimize technical and financial risk as well as lead times for prototyping and introduction into series production. Based on this knowledge together with a unique free-form micro-lens array production technology and patented micro-optics beam shaping designs a number of novel production tool sub-systems have been built by LIMO: 1. a multi-kilowatt direct diode illumination modules for solar cell annealing, and crystallization; 2. a novel green laser beam line for the annealing of silicon thin films on glass; 3. a novel wavefront shaping optics that generates a top hat beam profile from a TEM00 high-power laser source for accurate thin film structuring. For each of these sub-system basic functionalities, design principles and performance results are presented with a special emphasis on resilience, cost reduction and process reliability.
6
Yu, Min-Wen, Satoshi Ishii, Shisheng Li, Ji-Ren Ku, Jhen-Hong Yang, Kuan-Lin Su, Takaaki Taniguchi, Tadaaki Nagao e Kuo-Ping Chen. "Observation of carrier transports at exciton-plasmon coupling in MoS2 monolayers and 1D plamsmonic nanogrooves". In JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2021. http://dx.doi.org/10.1364/jsap.2021.10a_n404_6.
Testo completoAbstract (sommario):
Two-dimensional transition metal dichalcogenides (TMDCs) have studied intensively owing to their unique optical and electronic properties [1]. Among TMDCs, monolayer molybdenum disulfide (MoS2) is a direct bandgap semiconductor with strong binding energies which make it as a perfect candidate for light-matter coupling system. In the current work, we fabricated hybrid systems of MoS2 monolayers [2] and 1D plasmonic nanogrooves made of gold (Au) to study exciton-plasmon coupling, particularly the carrier transport at the coupling state (see Fig. 1(a)). The nanogrooves were suited to excite in-plane plasmons, which are different from metallic-nanoparticle-on-mirror configuration.(/p)(p)The exciton-plasmon couplings were confirmed by the reflectance measurements and the dispersion relations were plotted from the reflectance measurements as shown in Fig. 1(b). In Fig. 1(b), the plasmon-exciton coupling of the upper polariton and lower polariton were plotted as a function of detuning. The splitting energy was as large as 65 meV, which is one of the largest among the values reported so far at room temperature. The exciton-plasmon coupling has also been confirmed by the Kelvin probe force microscope (KPFM) which recorded the surface potentials. As shown in Fig. 1(c), while there was no surface potential change for the MoS2 on planar Au film, a surface potential shift of 13.5 meV was observed for the MoS2 on nanogroove upon laser irradiation at 532 nm. This is a direct evidence that surface potential shift was induced at the exciton-plasmon coupling. Our results indicated that the 1D plasmonic nanogrooves are appropriate structures to study exciton-plasmon coupling with large splitting energy at room temperature.
7
Krishnamoorthy, A. V., J. E. Ford, K. W. Goossen, J. A. Walker, A. L. Lentine, L. A. D’Asaro, S. P. Hui et al. "Implementation of a Photonic Page Buffer Based on GaAs MQW Modulators Bonded Directly over Active Silicon VLSI Circuits". In Optical Computing. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/optcomp.1995.pd2.
Testo completoAbstract (sommario):
The tremendous progress in high performance Very-Large Scale Integrated circuit (VLSI) technology has made possible the incorporation of several million transistors onto a single silicon chip with on-chip clock rates of 200 MegaHertz (MHz). By the end of decade, the integration density for silicon Complementary Metal Oxide Semiconductor (CMOS) is expected to be over 20 million transistors and the projected on-chip clock rate is 500 MHz. This enormous bandwidth that will be available for computation and switching on a silicon integrated circuit will create a huge bottleneck for Input and Output (I/O) to the VLSI circuit. Technologies that are being developed at AT&T Bell Laboratories, now exist for attaching GaAs Multiple Quantum Well (MQW) photodetectors and light-modulators onto a prefabricated silicon integrated circuit using a well-established hybrid flip-chip bonding technique followed by substrate removal of the GaAs chip to allow surface-normal operation of the optical modulators at 850nm [1]. From a systems point of view, the demands made of optoelectronic integration method are (i) that the silicon integrated circuit be state-of-the-art, (ii) the circuit be unaffected by the integration process, (iii) that the design and optimization of the circuit proceed independently of the placement and bonding to the optical I/O. The first two goals have been achieved in reference 1, and this technique has been effectively applied to simple switching nodes for a smart-pixel based photonic switch in reference 2. In this paper we further achieve the third goal by demonstrating for the first time that modulators can be bonded directly above active submicron CMOS transistors (figure 1), and by applying the technique to the demonstration of a high-density 2Kbit first-in first-out (Fifo) page buffer circuit.