Готові списки джерел за темами / Photoluminescence - Nanostructures

Добірка наукової літератури з теми "Photoluminescence - Nanostructures"

Автор: Grafiati
Опубліковано: 7 вересня 2023

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Статті в журналах з теми "Photoluminescence - Nanostructures"

1

Zhang, Shiying, Huizhao Zhuang, Chengshan Xue та Baoli Li. "Effect of Annealing on Morphology and Photoluminescence of β-Ga2O3 Nanostructures". Journal of Nanoscience and Nanotechnology 8, № 7 (1 липня 2008): 3454–57. http://dx.doi.org/10.1166/jnn.2008.138.

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A novel method was applied to prepare one-dimensional β-Ga2O3 nanostructure films. In this method, β-Ga2O3 nanostructures have been successfully synthesized on Si(111) substrates through annealing sputtered Ga2O3/Mo films for differernt time under flowing ammonia. The as-synthesized β-Ga2O3 nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results show that the formed nanostructures are single-crystalline Ga2O3 with monoclinic structure. The annealing time of the samples has an evident influence on the morphology and optical property of the nanostructured β-Ga2O3 synthesized. The representative photoluminescence spectrum at room temperature exhibits a strong and broad emission band centered at 411.5 nm and a relatively weak emission peak located at 437.6 nm. The growth mechanism of the β-Ga2O3 nanostructured materials is also discussed briefly.
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2

Gong, Jiang Feng, Wei Hua Zhu, Kai Xiao Zhang, Ming Yi Liu, and Hai Yan Xie. "Synthesis Aligned ZnS Nanocone and its Photoluminescence." Advanced Materials Research 295-297 (July 2011): 610–13. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.610.

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We report the synthesis and characterization of ZnS nanostructures, which were grown by thermal evaporation of the ZnS powder at high temperature using iron network as the collection substrate. Scanning electron microscopy investigations show that the products present taper-like morphologies. Transmission electron microscopy studies indicate ZnS nanostructures are well crystallized. The formation mechanism of the novel nanostructure is discussed on the basis of the experimental results; The nanostructure is formed due to a fast growth of ZnS nanowire along [0001] and the subsequent “epitaxial” radial growth of the ZnS nanocone along the six (01-10) surfaces around the nanowire. A strong room-temperature photoluminescence in ZnS nanostructures has been demonstrated.
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3

Botsoa, Jacques, Jean Marie Bluet, Vladimir Lysenko, Olivier Marty, Daniel Barbier, and Gérard Guillot. "Photoluminescence of 6H-SiC Nanostructures." Materials Science Forum 556-557 (September 2007): 407–10. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.407.

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Photoluminescence properties of a freestanding nanoporous SiC layer obtained from bulk 6H-SiC substrate as well as SiC nanopowder consisting of numerous separated nanoparticles has been investigated. The nanoporous SiC layer is obtained by UV radiation assisted electrochemical etching of the 6H-SiC wafer and the SiC nanopowder is formed by mechanical grinding of the nanoporous SiC free layer. A comparison of low temperature PL spectra of the SiC nanostructures and initial SiC bulk substrate has been performed. The evolution of PL spectra of the SiC nanostructures with respect to their surface states and excitation laser power has been studied. In particular, the well pronounced high energy tail above the excitonic bandgap in the PL spectra of the nanostructured SiC is attributed to quantum confinement effects. The strong PL signal obtained below the bandgap is explained by radiative transitions involving surface states, N-Al donoracceptor recombination levels and deep levels corresponding to volume defects in the SiC nanocrystallites.
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4

Husairi, F. S., K. Eswar, Z. N. Atikah, A. Azlinda, M. Rusop, and S. Abdullah. "The Fabrication of PSi/ZnO Nanostructures as Chemical Sensors for the Detection of Ethanol in Solution Using an Electrochemical Impedance Technique." Applied Mechanics and Materials 773-774 (July 2015): 642–46. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.642.

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In this work, porous silicon (PSi) was prepared by electrochemical etching and used as a template for ZnO nanostructures. ZnO nanostructures were grown using the catalytic immersion method at different molar ratio concentrations of the precursor and stabilizer. The ZnO nanostructures were analyzed using FESEM and photoluminescence (PL) spectrometry, before tested with ethanol solution. The population of the ZnO nanostructures on PSi increased with the concentration and followed the surface morphology of PSi. The photoluminescence spectra of ZnO show two dominant peaks in the UV and visible regions. When the concentration of the precursor increased, the PL peaks in the visible region (630 nm) shifted towards the blue region of the spectrum. The PSi/ZnO nanostructure chemical sensor has a large surface area, reversing sensor and fast response in ethanol. The performance of the sensor was affected by the morphology and defect structures of the ZnO nanostructures layer.
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5

Скурлов, И. Д., П. С. Парфёнов, А. В. Соколова, Д. А. Татаринов, А. А. Бабаев, М. А. Баранов та А. П. Литвин. "Фотоиндуцированный перенос заряда в слоистых 2D наноструктурах PbSe-MoS-=SUB=-2-=/SUB=-". Оптика и спектроскопия 130, № 2 (2022): 325. http://dx.doi.org/10.21883/os.2022.02.52003.2773-21.

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Semiconductor 2D nanostructures are a new platform for the creation of modern optoelectronic devices. Layered 2D PbSe-MoS2 nanostructures with efficient photoinduced charge transfer from PbSe nanoplatelets (NPLs) to MoS2 were created. When PbSe NPLs with short organic ligands are deposited onto a thin layer of MoS2 NPLs, a decrease in their photoluminescence intensity and a decrease in the average photoluminescence lifetime are observed. When a layered 2D PbSe-MoS2 nanostructure is illuminated with IR radiation, a photocurrent appears, which indicates the contribution of PbSe NPLs to the electrical response of the system. Ultrathin layers of transition metal dichalcogenides sensitized with nanostructures based on lead chalcogenides can be used in photodetectors with a spectral sensitivity region extended to the near-IR range.
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6

Husairi, F. S., Syahirah Mhd Ali, A. Azlinda, M. Rusop, and S. Abdullah. "Special Effect of Urea as a Stabilizer in Thermal Immersion Method to Synthesis Porous Zinc Oxide Nanostructures." Journal of Nanomaterials 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/163527.

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ZnO nanostructure was prepared by catalytic immersion method (90°C) with zinc nitrate hexahydrate (Zn(NO3)26H2O) as a precursors and urea (CH4N2O) as a stabilizer. Different molarity concentration ratio of Zn(NO3)26H2O to CH4N2O, 2 : 1, 1 : 4, 1 : 6, and 1 : 8 is used in this work. The effect of urea concentration used during the synthesis process is discussed. The ZnO nanostructures were characterized by using field emission scanning electron microscope (FESEM), photoluminescene (PL), andI-Vprobe. Porous nanoflakes are successfully synthesized on p-type silicon substrate coated with gold layer with different size and dimension. High intensity photoluminescence (PL) at optimum concentration indicated that urea is good stabilizer to produce ZnO nanostructures with good crytallinity. Rectifying characteristics show dramaticaly change in turn-on voltage when the concentration of urea increases in aqueous solution. This is related to the theory about p-type doping of ZnO nanostructures by nitrogen from NH3.
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7

Jalolov, R. R., B. N. Rustamova, Sh Z. Urolov, and Z. Sh Shaymardanov. "The influence of size on the photoluminescence properties of ZnO nanostructures." «Узбекский физический журнал» 23, no. 2 (September 14, 2021): 40–44. http://dx.doi.org/10.52304/.v23i2.238.

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This paper describes methods for synthesizing different nanostructures of ZnO in aqueous solutions at low temperatures and examines the effect of the size of the synthesized samples on the photoluminescence (PL) spectra. As the diameters of the nanostructures increased, a decrease in the ratio of the intensity of the ultraviolet radiation band to the intensity of the yellow radiation band in the PL spectrum observed. It is found that changing the diameters of nanostructures from 15 nm to 1000 nm leads to a decrease in their bandgap energy (Eg) from 3.28 to 3.21 eV. When the diameters of the nanostructures were less than ~400 nm, it was found that the energy of the band gap was strongly depend on the size of the nanostructure, and that the bond was weaker as the size of the nanostructures exceeded 400 nm.
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8

Galdámez-Martinez, Andres, Guillermo Santana, Frank Güell, Paulina R. Martínez-Alanis, and Ateet Dutt. "Photoluminescence of ZnO Nanowires: A Review." Nanomaterials 10, no. 5 (April 29, 2020): 857. http://dx.doi.org/10.3390/nano10050857.

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One-dimensional ZnO nanostructures (nanowires/nanorods) are attractive materials for applications such as gas sensors, biosensors, solar cells, and photocatalysts. This is due to the relatively easy production process of these kinds of nanostructures with excellent charge carrier transport properties and high crystalline quality. In this work, we review the photoluminescence (PL) properties of single and collective ZnO nanowires and nanorods. As different growth techniques were obtained for the presented samples, a brief review of two popular growth methods, vapor-liquid-solid (VLS) and hydrothermal, is shown. Then, a discussion of the emission process and characteristics of the near-band edge excitonic emission (NBE) and deep-level emission (DLE) bands is presented. Their respective contribution to the total emission of the nanostructure is discussed using the spatial information distribution obtained by scanning transmission electron microscopy−cathodoluminescence (STEM-CL) measurements. Also, the influence of surface effects on the photoluminescence of ZnO nanowires, as well as the temperature dependence, is briefly discussed for both ultraviolet and visible emissions. Finally, we present a discussion of the size reduction effects of the two main photoluminescent bands of ZnO. For a wide emission (near ultra-violet and visible), which has sometimes been attributed to different origins, we present a summary of the different native point defects or trap centers in ZnO as a cause for the different deep-level emission bands.
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9

Skurlov I. D., Parfenov P. S., Sokolova A. V., Tatarinov D. A., Babaev A. A., Baranov M. A., and Litvin A. P. "Photoinduced charge transfer in layered 2D PbSe-MoS-=SUB=-2-=/SUB=- nanostructures." Optics and Spectroscopy 132, no. 2 (2022): 298. http://dx.doi.org/10.21883/eos.2022.02.53226.2773-21.

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Анотація:
Semiconductor 2D nanostructures are a new platform for the creation of modern optoelectronic devices. Layered 2D PbSe-MoS2 nanostructures with efficient photoinduced charge transfer from PbSe nanoplatelets (NPLs) to MoS2 were created. When PbSe NPLs with short organic ligands are deposited onto a thin layer of MoS2 NPLs, a decrease in their photoluminescence intensity and a decrease in the average photoluminescence lifetime are observed. When a layered 2D PbSe-MoS2 nanostructure is illuminated with IR radiation, a photocurrent appears, which indicates the contribution of PbSe NPLs to the electrical response of the system. Ultrathin layers of transition metal dichalcogenides sensitized with nanostructures based on lead chalcogenides can be used in photodetectors with a spectral sensitivity region extended to the near-IR range. Keywords: nanoplatelets, transition metal dichalcogenides, charge transfer, near infrared region.
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10

Wang, S. L., H. W. Zhu, W. H. Tang, and P. G. Li. "Propeller-Shaped ZnO Nanostructures Obtained by Chemical Vapor Deposition: Photoluminescence and Photocatalytic Properties." Journal of Nanomaterials 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/594290.

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Propeller-shaped and flower-shaped ZnO nanostructures on Si substrates were prepared by a one-step chemical vapor deposition technique. The propeller-shaped ZnO nanostructure consists of a set of axial nanorod (50 nm in tip, 80 nm in root and 1 μm in length), surrounded by radial-oriented nanoribbons (20–30 nm in thickness and 1.5 μm in length). The morphology of flower-shaped ZnO nanostructure is similar to that of propeller-shaped ZnO, except the shape of leaves. These nanorods leaves (30 nm in diameter and 1–1.5 μm in length) are aligned in a radial way and pointed toward a common center. The flower-shaped ZnO nanostructures show sharper and stronger UV emission at 378 nm than the propeller-shaped ZnO, indicating a better crystal quality and fewer structural defects in flower-shaped ZnO. In comparison with flower-shaped ZnO nanostructures, the propeller-shaped ZnO nanostructures exhibited a higher photocatalytic property for the photocatalytic degradation of Rhodamine B under UV-light illumination.
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Більше джерел

Дисертації з теми "Photoluminescence - Nanostructures"

1

Sun, Ye. "Synthesis and photoluminescence of ZnO nanostructures." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440141.

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2

Feng, Lin. "Photoluminescence studies of single zinc oxide nanostructures /." View abstract or full-text, 2010. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202010%20FENG.

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3

Toft, Ian. "Fibre optic micro-photoluminescence of quantum nanostructures." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614103.

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4

Chauvin, Nicolas. "Spectroscopie de la boîte quantique unique dans les systèmes InAs sur InP et InAs sur GaAs émettant à 1,3 µm : application aux sources localisées." Lyon, INSA, 2006. http://theses.insa-lyon.fr/publication/2006ISAL0051/these.pdf.

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Les boîtes quantiques soulèvent actuellement un vif intérêt dans le domaine du traitement quantique de l'information qui nécessite l'utilisation de photons uniques pour la cryptographie ou le calcul quantique. Il est donc nécessaire de comprendre la physique des boîtes quantiques uniques InAs/GaAs et InAs/InP émettant dans la gamme spectrale 1,3 à 1,5 µm, longueurs d'onde adaptées pour la transmission dans les fibres optiques. Dans cette thèse, nous avons étudié le système exciton-biexciton, la structure fine, l'impact de la température ainsi que les excitons chargés pour une boîte quantique unique. Les études en fonction de la température ont montré que les largeurs à mi-hauteur sont de l'ordre du meV à la température de l'azote liquide et se situent entre 10 et 15 meV à température ambiante pour les boîtes InAs/GaAs. De plus, nous avons observé l'évolution de l'énergie de lisaison du biexciton et de la structure fine en fonction de la taille des boîtes InAs/InP
Quantum dots are very promising in the field of quantum information which requires the use of single photons for quantum cryptography or quantum calculation. Thus, it is necessary to understand the physic of single InAs/GaAs and InAs/InP quantul dots emitting in 1. 3 to 1. 5 micrometer spectral range, wavelengths adapted for the transmission through optical fibres. In this thesis, we studied the exciton-biexciton complex, the fine structure splitting, the impact of the temperature and charged excitons in single quantum dots. We observed the dependence of the biexciton binding energy and of the fine structure splitting as a function of the InAs/InP quantum dot size. Moreover, the studies as a function of the temperature showed that the linewidth of the exciton recombination is in the meV range nitrogen temperature and in the 10-15 me V range at room temperature for the InAs/GaAs dots
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5

Küster, Achim [Verfasser]. "Photoluminescence of nanostructures in droplet-etched nanoholes / Achim Küster." München : Verlag Dr. Hut, 2018. http://d-nb.info/1172582041/34.

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6

Van, Hattem Barbara. "Orientation-dependent magneto-photoluminescence of excitons confined in semiconductor nanostructures." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708560.

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7

Filippov, Stanislav. "Micro-photoluminescence and micro-Raman spectroscopy of novel semiconductor nanostructures." Doctoral thesis, Linköpings universitet, Funktionella elektroniska material, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-123939.

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Анотація:
Low-dimensional semiconductor structures, such as one-dimensional nanowires (NWs) and zerodimensional quantum dots (QDs), are materials with novel fundamental physical properties and a great potential for a wide range of nanoscale device applications. Here, especially promising are direct bandgap II-VI and III-V compounds and related alloys with a broad selection of compositions and band structures. For examples, NWs based on dilute nitride alloys, i.e. GaNAs and GaNP, provide both an optical active medium and well-shaped cavity and, therefore, can be used in a variety of advanced optoelectronic devices including intermediate band solar cells and efficient light-emitters. Self-assembled InAs QDs formed in the GaAs matrix are proposed as building blocks for entangled photon sources for quantum cryptography and quantum information processing as well as for spin light emitting devices. ZnO NWs can be utilized in a variety of applications including efficient UV lasers and gas sensors. In order to fully explore advantages of nanostructured materials, their electronic properties and lattice structure need to be comprehensively characterized and fully understood, which is not yet achieved in the case of aforementioned material systems. The research work presented this thesis addresses a selection of open issues via comprehensive optical characterization of individual nanostructures using micro-Raman ( -Raman) and micro-photoluminescence ( -PL) spectroscopies. In paper 1 we study polarization properties of individual GaNP and GaP/GaNP core/shell NWs using polarization resolved μ-PL spectroscopy. Near band-edge emission in these structures is found to be strongly polarized (up to 60% at 150K) in the orthogonal direction to the NW axis, in spite of their zinc blende (ZB) structure. This polarization response, which is unusual for ZB NWs, is attributed to the local strain in the vicinity of the N-related centers participating in the radiative recombination and to their preferential alignment along the growth direction, presumably caused by the presence of planar defects. Our findings therefore show that defect engineering via alloying with nitrogen provides an additional degree of freedom to control the polarization anisotropy of III-V nanowires, advantageous for their applications as a nanoscale source of polarized light. Structural and optical properties of novel coaxial GaAs/Ga(N)As NWs grown on Si substrates, were evaluated in papers 2-4. In paper 2 we show by using -Raman spectroscopy that, though nitrogen incorporation shortens a phonon correlation length, the GaNAs shell with [N]<0.6% has a low degree of alloy disorder and weak residual strain. Additionally, Raman scattering by the GaAs-like and GaNlike phonons is found to be enhanced when the excitation energy approaches the E+ transition energy. This effect was attributed the involvement of intermediate states that were created by N-related clusters in proximity to the E+ subband. Recombination processes in these structures were studied in paper 3 by means of μ-PL, μ-PL excitation (μ-PLE), and time-resolved PL spectroscopies. At low temperatures, the alloy disorder is found to localize photo-excited carriers leading to predominance of localized exciton (LE) transitions in the PL spectra. Some of the local fluctuations in N composition are suggested to create three-dimensional confining potentials equivalent to that for QDs, based on the observation of sharp PL lines within the LE contour. In paper 4 we show that the formation of these QD-like confinement potentials is somewhat facilitated in spatial regions of the NWs with a high density of structural defects, based on correlative spatially-resolved structural and optical studies. It is also concluded the principal axis of these QD-like local potentials is mainly oriented along the growth direction and emit light that is linearly polarized in the direction orthogonal to the NW axis. At room temperature, the PL emission is found to be dominated by recombination of free carriers/excitons and their lifetime is governed by non-radiative recombination via surface states. The surface recombination is found to become less severe upon N incorporation due to N-induced modification of the surface states, possibly due to partial surface nitridation. All these findings suggest that the GaNAs/GaAs hetero-structures with the onedimensional geometry are promising for fabrication of novel optoelectronic devices on foreign substrates (e.g. Si). Fine-structure splitting (FSS) of excitons in semiconductor nanostructures has significant implications in photon entanglement, relevant to quantum information technology and spintronics. In paper 5 we study FSS in various laterally-arranged single quantum molecular structures (QMSs), including double QDs (DQDs), quantum rings (QRs), and QD-clusters (QCs), by means of polarization resolved μ-PL spectroscopy. It is found that FSS strongly depends on the geometric arrangements of the QMSs, which can effectively tune the degree of asymmetry in the lateral confinement potential of the excitons and can reduce FSS even in a strained QD system to a limit similar to strain-free QDs. Fabrication of nanostructured ZnO-based devices involves, as a compulsory step, deposition of thin metallic layers. In paper 6 we investigate impact of metallization by Ni on structural quality of ZnO NWs by means of Raman spectroscopy. We show that Ni coating of ZnO NWs causes passivation of surface states responsible for the enhanced intensity of the A1(LO) in the bare ZnO NWs. From the resonant Raman studies, strong enhancement of the multiline Raman signal involving A1(LO) in the ZnO/Ni NWs is revealed and is attributed to the combined effects of the Fröhlich interaction and plasmonic coupling. The latter effect is also suggested to allow detection of carbon-related species absorbed at the surface of a single ZnO/Ni NW, promising for utilizing such structures as efficient nano-sized gas sensors.
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8

Sousa, Nobre Sónia de. "Hybrides Organiques/Inorganiques Nanostructurés Photoluminescents." Montpellier 2, 2009. http://www.theses.fr/2009MON20212.

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Les travaux rapportés ont pour objet la caractérisation des propriétés structurales et de photoluminescence d'une série d'hybrides organiques-inorganiques. Leurs matrices comportent des groupements urée capables d'autoassemblage reliant le réseau silicate et un fragment organique. L'origine et les transferts d'énergie conduisant à l'émission de lumière ont été étudiés dans le cas des hybrides à base de polyéthers, contenant ou non des ions métalliques Eu3+ et préalablement caractérisés au laboratoire, afin de dresser une toile de fond théorique pour aider l'interprétation des données expérimentales et la conception de nouveaux matériaux hybrides. L'effet de la morphologie sur les propriétés de photoluminescence a ensuite été étudié : des hybrides comportant un fragment central alkyle avec des morphologies différentes ont été obtenus à partir d'un précurseur unique en utilisant des conditions acide ou nucléophile, en présence ou non d'ions Eu3+. Des matériaux hybrides lamellaires ou amorphes ont été obtenus et la comparaison des propriétés de photoluminescence a montré que ces derniers possèdent de meilleurs rendements quantiques. Des matériaux hybrides comportant un fragment bipyridine ont été synthétisés. Ceux sans métal sont stables dans le temps, excitables avec des LEDs commerciales et bon marché, et ont un très bon rendement quantique (0. 18 et 0. 22±0. 02) pour des excitations dans le long UV/bleu. Les mêmes hybrides synthétisés en présence de sels d'Eu3+, Gd3+ et/ou Tb3+ ont aussi été synthétisés et le rôle clef joué par la lumière émise par l'hôte dans la luminescence de ces hybrides a été démontré
The present work focus on the characterization of the structural and photoluminescence properties of a series of organic-inorganic hybrids. The matrix of these materials includes urea crosslinks between a siliceous backbone and an organic chain (polyether, alkylene and bipyridine based). The origin and energy transfer processes behind the emission features was studied for the polyether-based organic/inorganic hybrids lacking metal activator and incorporating Eu3+ (that were well characterized in previous works) in order to have a theoretical scheme that will be useful in guiding the interpretation of experimental data and in the design of new organic/inorganic hybrids. The effect of the morphology on the photoluminescence features of hybrids was also studied; alkyl-based hybrids with different morphologies were obtained from the same precursor (designated P12) using acidic or nucleophilic catalysis, in the presence of Eu3+, giving lamellar and amorphous hybrids lamellar materials and the respective structural and luminescence features compared. Two amorphous bipyridine-based materials were synthesized exhibiting high stability over time and high emission quantum yield values (0. 18±0. 02 and 0. 22±0. 02) for excitation in the long UV/blue regions using a commercial light emitting diode (LED). These bipyridine-based hybrids incorporating Eu3+, Gd3+, and/or Tb3+ ions were also synthesized and the key role played by the light emitted by the hybrid host in the luminescence of the corresponding Ln3+-based hybrids was demonstrated
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9

Noé, Pierre-Olivier. "Elaboration et caractérisation de matériaux nanostructurés à base de silicium comme source de lumière pour la photonique." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENY006.

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Анотація:
Le silicium est reconnu comme étant un mauvais émetteur de lumière à cause de son gap indirect. Diverses stratégies ont été développées pour améliorer son rendement d'émission, le Si constituant le matériau de choix pour la photonique. Ce manuscrit présente l'élaboration et la caractérisation de matériaux originaux à base de silicium afin de proposer des solutions alternatives pour améliorer les propriétés d'émission de lumière du Si. Ce travail est divisé en 4 parties avec tout d'abord une revue de l'état de l'art de l'émission de lumière dans le Si et les bases sur les mécanismes de recombinaison dans le Si. Une seconde partie se concentre sur l'élaboration et l'étude de dispositifs électroluminescents à base de Si comportant un réseau de dislocations enterrées un niveau d'une jonction PN obtenu par collage moléculaire. L'émission de lumière située vers 1,1 et 1,5 µm (1,1 et 0,8 eV) est attribuée à la recombinaison des porteurs sur les états piège induits par des précipités de bore et d'oxyde dans le voisinage de dislocations (E^phonon_Bore vers 1.1eV et Dp~0.8eV) et des états de défauts localisés à l'intersection du réseau carré de dislocations vis (D1~0.8eV). Une troisième partie traite de l'élaboration et des propriétés optique d'ions Er3 + couplés avec des nanostructures de Si dans des films minces de SRO (Silicon-Rich Oxide) obtenus par co-évaporation de SiO et d'Er. Dans cette matrice, l'efficacité d'excitation indirecte de l'Er à 1,5 µm via les nanostructures est démontrée par la mesure de sections efficaces effectives d'excitation de l'Er entre 2x10-16 cm2 et 5x10-15 cm2 en fonction du flux d'excitation et des paramètres d'élaboration. Le principal résultat est la forte diminution avec la température de recuit de la fraction d'ions Er3+ émetteurs susceptible d'être inversée. Des expériences EXAFS révèlent que ce comportement est en corrélation avec l'évolution de l'ordre chimique local autour des atomes d'Er. Dans une dernière partie est présentée l'élaboration de nanostructures de Si de type nanofils cœur-coquille Si/SiO2. Ces structures cœur-coquille sont obtenues par trois méthodes différentes. Les structures obtenues par dépôt d'oxyde sur la surface de nanofils de silicium CVD catalysées avec de l'Au présentent une émission autour de 500 nm efficace à température ambiante due à la recombinaison des porteurs photo-générés au niveau des états de défauts dans la couche d'oxyde et à l'interface Si/SiO2. L'intensité de PL collectée est de plus d'un ordre de grandeur supérieure à celle mesurée sur des films minces de SiO2 similaires déposés sur des substrats de Si. En outre, la passivation des nanofils de Si CVD par un procédé d'oxydation thermique permet de neutraliser les états de surface qui dominent dans de telles structures. La mesure des vitesses de recombinaison de surface semble indiquer que ces nanofils ainsi passivés présentent des propriétés électroniques de volume similaires à celles du Si standard de microélectronique. Enfin, une nouvelle méthode pour l'élaboration in situ de nanofils cœur-coquille Si/SiO2 basée sur l'évaporation d'une source solide SiO avec l'Au et le Cu comme catalyseurs est détaillée. La croissance des fils catalysés par l'Au se produit dans le mode de croissance VLS (Vapor-Liquid-Solid comme en CVD) donnnat des nanofils présentant un cœur de Si cristallin et une coquille amorphe d'oxyde. En revanche, la croissance des nanofils catalysée par le Cu semble se produire préférentiellement à plus basse température en mode VSS (Vapeur-Solide-Solide) expliquant pourquoi ces NFs présentent une forte densité de défauts cristallins dans la cœur de Si contrairement aux fils catalysés Au
Silicon is known as a poor light emitter due to its indirect band gap. Various strategies have been developed to overcome its poor emission efficiency since it is the material of choice for photonics. In this manuscript are detailed the elaboration and characterization of original silicon-based materials in order to propose alternatives solutions to improve Si light emission properties. This work is divided in 4 parts with a first one describing the state of the art of light emission in Si and the basics of recombination mechanisms in Si. A second part focuses on the elaboration and study of electroluminescent devices based on bulk Si with a buried dislocation network at a PN junction obtained by wafer bonding. The light emission near 1.1 and 1.5 µm (1.1 and 0.8 eV) is attributed to the recombination of carriers on trap states induced by boron and oxide precipitates in the vicinity of dislocations (E^phonon_Bore near 1.1eV and Dp~0.8eV) and defects traps at the intersection of the square network of screw dislocations (D1~0.8eV). In a third part is showed the elaboration and the optical properties of Er3+ ions coupled with Si nanostructures in Si-Rich Silicon Oxide (SRO) thin films obtained by co-evaporation of SiO and Er. We demonstrate the efficient indirect excitation of Er at 1.5 µm with high effective cross sections between 2x10-16 cm2 and 5x10-15 cm2 as a function of the excitation flux and the elaboration parameters. The main result is the drastic decrease of the number of Er3+ emitting ions coupled to Si with the annealing temperature. EXAFS experiments revealed that this behavior is correlated with the evolution of the local chemical order around Er atoms. In a last part is presented the elaboration of Si nanostructures based on core-shell Si/SiO2 nanowires. These core-shell structures are obtained by three different methods. Core-shell nanowires obtained by oxide deposition on the surface of CVD Au-catalyzed Si nanowires exhibit an efficient room temperature emission around 500 nm due to the recombination of photo generated carriers in defects states in the oxide layer and at the Si/SiO2 interface. The collected PL intensity is more than one order of magnitude higher than similar SiO2 thin films deposited on Si substrates. Moreover, the passivation of CVD-growth Si nanowires by a thermal oxidation procedure allows neutralizing the surface states which are predominant in such structures. As a result, the measurement of surface recombination velocities seems to indicate that such passivated nanowires present similar volume electronic properties than standard microelectronic bulk Si. Finally, a new method for the elaboration of in situ core-shell Si/SiO2 nanowires based on the evaporation of a solid SiO source with Au and Cu as catalysts is presented. The Au-catalyzed growth occurs in the VLS mode (Vapor-Liquid-Solid like in CVD-growth) leading to the growth of nanowires with a crystalline Si core surrounded by an amorphous oxide shell. But Cu-catalyzed nanowires growth seems to appear preferentially at lower temperatures in the VSS (Vapour-Solid-Solid) mode explaining why these nanowiress exhibit a high density of crystalline defects in the Si core compared to Au-catalyzed wires
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10

Maabou, Serge. "Eau surfondue et (bi)polarons dans les nanostructures." Angers, 2006. http://www.theses.fr/2006ANGE0023.

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Nous étudions par dynamique moléculaire la présence des hétérogénéités dynamiques dans l'eau surfondue. Nous utilisons le récent modèle TIP5P de Mahoney et Jorgensen qui est aujourd'hui le potentiel qui reproduit le mieux les propriétés de l'eau que nous étudions. Les résultats de nos simulations sont en bon accord avec ceux obtenus expérimentalement ce qui nous a permis de valider notre programme. Par la suite, nous montrons l'existence d'hétérogénéités dynamiques dans l'eau surfondue. Nous avons étudié les agrégations dynamiques des molécules de mobilités différentes. Nous observons l'agrégation dynamique des molécules les plus mobiles ainsi que leurs mouvements sous forme de chaînes d'hétérogénéités. Les molécules les moins mobiles quant à elles forment des groupements dont la taille augmente lorsque la température baisse. Nous observons la présence de deux temps caractéristiques associés au deux types d'hétérogénéités et évoluant différemment. Nous montrons la présence d'effets de taille finie dans l'eau surfondue qui s'accroissent lorsque la température baisse. Dans l'autre partie de ce travail, nous avons étudié les propriétés des porteurs de charges dans les nano structures de type OD, 1D, 3D. Nous effectuons des calculs théoriques des caractéristiques (énergie et masse) du (bi)polaron dans les nanostructures à l'aide de la méthode variationnelle de Feynman. Nous obtenons la relation entre ces caractéristiques, le rayon, l'anisotropie et la constante de couplage électron-phonon de Fröhlich. Par optimisation numérique, nous montrons l'évolution de ces caractéristiques au fondamental de niveaux d'énergies. Nous développons une théorie de photoluminescence assisté par des phonons dans un nano cristal sphérique pour différents mécanismes d'interaction entre les électrons et les phonons
We investigate the presence of dynamical heterogeneities in supercooled water with molecular dynamics simulation. The new water model TIP5P proposed by Mahoney and Jorgensen which reproduces well water properties is used. We validate our simulation by a compartive study of our results and those obtained in experiments. Thereafter, We show the existence of dynamic heterogeneities in supercooled water. We then studied dynamic aggregations of the molecules of different mobilities and find a string-like dynamics for the most mobile molecules and also dynamical aggregation of the least mobile molecules. The two kinds of dynamical aggregation appear however to be very different. We observes two different times characteristic associated to the two types of heterogeneities. Many sizes of boxes are used for simulations and we show the finite size effect on static and dynamic properties of supercooled water. In the second part of this work, we studied the properties of the charge carriers in mesoscopic structures type OD, 1D, 3D. Using Feynman variational method we carry out theoretical calculations of the characteristics (energy and mass) of the (bi)polaron in nanostructures. We obtain the relation between these characteristics, radius, anisotropy and the Fröhlich electron-phonon coupling constant. By numerical optimization, we obtained that the ground state energy and mass of (bi)polaron increase with the coupling constant and confinement frequency. We developed a theory of photoluminescence assisted by phonons in a spherical nano crystal for various mechanisms of interaction between the electrons and the phonons
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Книги з теми "Photoluminescence - Nanostructures"

1

Challa S.S.R. Kumar. UV-VIS and Photoluminescence Spectroscopy for Nanomaterials Characterization. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013.

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2

Al-Ajili, Adwan Nayef Hameed. Photoluminescence of nanostructured silicon. 1996.

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Uvvis And Photoluminescence Spectroscopy For Nanomaterials Characterization. Springer, 2012.

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4

Challa S.S.R. Kumar. UV-VIS and Photoluminescence Spectroscopy for Nanomaterials Characterization. Springer, 2016.

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Частини книг з теми "Photoluminescence - Nanostructures"

1

Kalt, Heinz. "Nano-Photoluminescence." In CFN Lectures on Functional Nanostructures Vol. 1, 51–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-31533-9_3.

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2

Botsoa, Jacques, Jean Marie Bluet, Vladimir Lysenko, Olivier Marty, Daniel Barbier, and Gérard Guillot. "Photoluminescence of 6H-SiC Nanostructures." In Materials Science Forum, 407–10. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-442-1.407.

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3

Avashthi, Gopal, Shrikant S. Maktedar, and Man Singh. "Sonochemically Covalent Functionalized Graphene Oxide Towards Photoluminescence and Nanocytotoxicity Activities." In Carbon Nanostructures, 105–26. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9057-0_4.

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4

Sohal, Sandeep, Xianwen Zhang, Archis Marathe, V. V. Kuryatkov, Marauo Davis, Louisa J. Hope-Weeks, Jharna Chaudhuri, and Mark Holtz. "Photoluminescence Properties of Hierarchical YBO3:Eu3+Nanostructures." In TMS2013 Supplemental Proceedings, 119–25. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118663547.ch16.

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5

Scaffardi, Lucía B., Daniel C. Schinca, Marcelo Lester, Fabián A. Videla, Jesica M. J. Santillán, and Ricardo M. Abraham Ekeroth. "Size-Dependent Optical Properties of Metallic Nanostructures." In UV-VIS and Photoluminescence Spectroscopy for Nanomaterials Characterization, 179–229. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-27594-4_5.

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6

Torres, C. M. Sotomayor, M. Watt, H. E. G. Arnot, R. Glew, W. E. Leitch, A. H. Kean, R. Cusco Cornet, et al. "Raman Scattering and Photoluminescence of GaAs-Based Nanostructures." In Science and Engineering of One- and Zero-Dimensional Semiconductors, 297–307. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-5733-9_28.

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7

Babiński, A. "Photoluminescence from InGaAs/GaAs Quantum Dots in a High Electric Field." In Optical Properties of Semiconductor Nanostructures, 395–404. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4158-1_39.

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8

Park, Jeong-Eun, Minho Kim, Jiwoong Son, Chungyeon Lee, Sung Min Ko, and Jwa-Min Nam. "Metal Nanostructures with Plasmonically Enhanced Raman and Photoluminescence Signals." In 21st Century Nanoscience – A Handbook, 7–1. Boca Raton, Florida : CRC Press, [2020]: CRC Press, 2020. http://dx.doi.org/10.1201/9780429351617-7.

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9

Trenkmann, Ines, Thomas Blaudeck, and Christian von. "Static and Dynamic Quenching of Quantum Dot Photoluminescence by Organic Semiconductors and Dye Molecules." In Self-Assembled Organic-Inorganic Nanostructures, 215–43. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2016. http://dx.doi.org/10.1201/9781315364544-5.

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10

Huy, P. T., T. T. An, N. D. Chien, and Do Jin Kim. "Temperature-Controlled Catalytic Growth and Photoluminescence Properties of ZnO Nanostructures." In Semiconductor Photonics: Nano-Structured Materials and Devices, 68–70. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-471-5.68.

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Тези доповідей конференцій з теми "Photoluminescence - Nanostructures"

1

Djurišić, A. B. "Green Photoluminescence in ZnO Nanostructures." In PHYSICS OF SEMICONDUCTORS: 27th International Conference on the Physics of Semiconductors - ICPS-27. AIP, 2005. http://dx.doi.org/10.1063/1.1994392.

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2

Podor, Balint, Akos Nemcsics, Janos Balazs, Janos Makai, and Andrea Stemmann. "Photoluminescence investigation of GaAs quantum nanostructures." In 2011 34th International Spring Seminar on Electronics Technology (ISSE). IEEE, 2011. http://dx.doi.org/10.1109/isse.2011.6053945.

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3

Shahbazyan, T. V. "Plasmon-enhanced photoluminescence from metal nanostructures." In 7th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (Metamaterials 2013). IEEE, 2013. http://dx.doi.org/10.1109/metamaterials.2013.6809038.

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4

Ocola, Leonidas E., David J. Gosztola, Angel Yanguas-Gil, Hyo-Seon Suh, and Aine Connolly. "Photoluminescence of sequential infiltration synthesized ZnO nanostructures." In SPIE OPTO, edited by Manijeh Razeghi. SPIE, 2016. http://dx.doi.org/10.1117/12.2209422.

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5

Kral, Karel, and Miroslav Mensi. "Photoluminescence of nanostructures with indirect band gap." In 2014 16th International Conference on Transparent Optical Networks (ICTON). IEEE, 2014. http://dx.doi.org/10.1109/icton.2014.6876586.

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6

Biagioni, P., D. Brida, J. S. Huang, J. Kern, L. Duò, B. Hecht, M. Finazzi, and G. Cerullo. "Dynamics of two-photon photoluminescence in gold nanostructures." In SPIE LASE, edited by Frank Träger, Jan J. Dubowski, and David B. Geohegan. SPIE, 2012. http://dx.doi.org/10.1117/12.908498.

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7

Le, Khai Q., and Hiromi Okamoto. "Dissymmetry between left- and right-handed circularly polarized photoluminescence enhancement of plasmonic nanostructures." In JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2017. http://dx.doi.org/10.1364/jsap.2017.5a_a410_2.

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We report here strong dissymmetry between left- and right-handed circularly polarized photoluminescence enhancement (PLE) induced by two-dimensional chiral gold nanostructures, which can be utilized to provide circularly polarized luminescence. We employed the dye molecule IR-125 as an emitter whose photoluminescence was enhanced by a near-field interaction between the chiral plasmon and the molecule. The difference between the PLE factors for left- and right-handed circular polarizations induced by the near-field enhancement was correlated to the dissymmetry of left- and right-handed extinction of the gold nanostructures.
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8

Fu, Xiao, Jinjin Cong, The Duong, Heping Shen, Klaus J. Weber, Kylie R. Catchpole, and Thomas P. White. "Time- and Excitation-dependent Photoluminescence Characterisation of CH3NH3PbI3 Perovskite films." In Optical Nanostructures and Advanced Materials for Photovoltaics. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/pv.2015.pth3b.4.

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9

Asli, N. A., S. F. M. Yusop, M. Rusop, S. Abdullah, Abdul Manaf Hashim, and Vijay K. Arora. "Raman and Photoluminescence Spectroscopy Studies On Porous Silicon Nanostructures." In ENABLING SCIENCE AND NANOTECHNOLOGY: 2010 International Conference On Enabling Science And Nanotechnology Escinano2010. AIP, 2011. http://dx.doi.org/10.1063/1.3586962.

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10

Asli, N. A., S. F. M. Yusop, M. Rusop, and S. Abdullah. "Raman and photoluminescence spectroscopy studies on porous silicon nanostructures." In 2010 International Conference on Enabling Science and Nanotechnology (ESciNano). IEEE, 2010. http://dx.doi.org/10.1109/escinano.2010.5701049.

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