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Littérature scientifique sur le sujet « Raman/PL »

Auteur : Grafiati

Publié le 9 novembre 2024

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Articles de revues sur le sujet "Raman/PL"

Pavić, Ivan, Joško Šoda, Vlatko Gašparić et Mile Ivanda. « Raman and Photoluminescence Spectroscopy with a Variable Spectral Resolution ». Sensors 21, n^o 23 (28 novembre 2021) : 7951. http://dx.doi.org/10.3390/s21237951.

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Raman and photoluminescence (PL) spectroscopy are important analytic tools in materials science that yield information on molecules’ and crystals’ vibrational and electronic properties. Here, we show results of a novel approach for Raman and PL spectroscopy to exploit variable spectral resolution by using zoom optics in a monochromator in the front of the detector. Our results show that the spectral intervals of interest can be recorded with different zoom factors, significantly reducing the acquisition time and changing the spectral resolution for different zoom factors. The smallest spectral intervals recorded at the maximum zoom factor yield higher spectral resolution suitable for Raman spectra. In contrast, larger spectral intervals recorded at the minimum zoom factor yield the lowest spectral resolution suitable for luminescence spectra. We have demonstrated the change in spectral resolution by zoom objective with a zoom factor of 6, but the perspective of such an approach is up to a zoom factor of 20. We have compared such an approach on the prototype Raman spectrometer with the high quality commercial one. The comparison was made on ZrO2 and TiO2 nanocrystals for Raman scattering and Al2O3 for PL emission recording. Beside demonstrating that Raman spectrometer can be used for PL and Raman spectroscopy without changing of grating, our results show that such a spectrometer could be an efficient and fast tool in searching for Raman and PL bands of unknown materials and, thereafter, spectral recording of the spectral interval of interest at an appropriate spectral resolution.

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Suga, Keishi, Ying-Chen Lai, Miftah Faried et Hiroshi Umakoshi. « Direct Observation of Amyloid β Behavior at Phospholipid Membrane Constructed on Gold Nanoparticles ». International Journal of Analytical Chemistry 2018 (2 décembre 2018) : 1–7. http://dx.doi.org/10.1155/2018/2571808.

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Amyloid β (Aβ) is a potential biomarker of Alzheimer’s disease (AD), and its fibrillation behavior is of interest and value. In this study, the Aβ behaviors on phospholipid membranes were observed by Membrane Surface-Enhanced Raman Spectroscopy (MSERS) method. Phospholipid (PL) membranes, consisting of DMPC and DMPS with a molar ratio of 9:1, were fabricated on gold nanoparticles with diameter of 100 nm (Au@PL). Enhancement of the Raman intensity of Au@PL was increased by Aβ, with enhancement factor about 40. The H-bonding network was disturbed in presence of NaCl which covered Au@PL and made Au@PL away from one another. When Aβ was applied with Au@PL, the H-bonding network was disturbed just after mixing. As the reaction reaches to equilibrium, Aβ attracted neighbouring Au@PL and induced aggregation of Au@PL which blocked the aggregation prone site of Aβ to inhibit further fibrillation. Based on our method, the Aβ behaviors at lipid membrane surface can be directly observed via enhanced Raman signals.

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CHUAH, L. S., Z. HASSAN, F. K. YAM et H. ABU HASSAN. « STRUCTURAL AND OPTICAL FEATURES OF POROUS SILICON PREPARED BY ELECTROCHEMICAL ANODIC ETCHING ». Surface Review and Letters 16, n^o 01 (février 2009) : 93–97. http://dx.doi.org/10.1142/s0218625x09012342.

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Porous silicon (PS) samples were prepared by electrochemical anodic etching of n-type (111) silicon wafers in HF solution. The structural, optical, and chemical features of the PS were investigated in terms of different etching durations. The porous samples were investigated by scanning electron microscopy (SEM), photoluminescence (PL), and Raman scattering. SEM images indicated that the pores increased with the etching duration; however, the etching duration has significant effect on the shape of the pores. PL measurements revealed that the porosity-induced PL intensity enhancement was only observed in the porous samples. Raman spectra showed shifting of PS Raman peak to lower frequency relative to non-porous silicon Raman peak.

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ZHANG, WEI-FENG, QIAN XING et YA-BIN HUANG. « MICROSTRUCTURES AND OPTICAL PROPERTIES OF STRONTIUM TITANATE NANOCRYSTALS PREPARED BY A STEARIC-ACID GEL PROCESS ». Modern Physics Letters B 14, n^o 19 (20 août 2000) : 709–16. http://dx.doi.org/10.1142/s0217984900000896.

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SrTiO3 nanocrystals with grain sizes from 26 to 86 nm were prepared by stearic-acid gel method. The microstructures, lattice vibration and luminescence spectra were examined by X-ray diffraction, infrared, Raman and photoluminescence (PL) spectroscopies. Hydroxyl defects were clearly found by infrared spectroscopy in the SrTiO3 nanocrystals. Raman measurement results showed that internal stress exists in the SrTiO3 nanocrystals, which induces first-order Raman scattering processes. Strong visible PL near 2.62 eV was observed under 3.54 eV light excitation in small SrTiO3 nanocrystals. Grain-size dependence of the PL spectrum is investigated and the origin for the PL is attributed to a charge transfer via intrinsic defects inside an oxygen octahedron.

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AMIRHOSEINY, M., Z. HASSAN et S. S. NG. « EFFECT OF CURRENT DENSITY ON OPTICAL PROPERTIES OF ANISOTROPIC PHOTOELECTROCHEMICAL ETCHED SILICON (110) ». Modern Physics Letters B 26, n^o 20 (5 juillet 2012) : 1250131. http://dx.doi.org/10.1142/s021798491250131x.

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Photoelectrochemical etched Si layers were prepared on n-type (110) oriented silicon wafer. The photoluminescence (PL), Fourier transformed infrared (FTIR) absorption and Raman spectroscopies of etched Si (110) at two different current densities were studied. Both samples showed PL peak in the visible spectral range situated from 650 nm to 750 nm. The corresponding changes in Raman spectra at different current density are discussed. The blue shift in the PL and Raman peaks is consequent of the quantum confinement effect and defect states of surface Si nanocrystallites complexes and hydrogen atoms of the photoelectrochemical etched Si (110) samples. The attenuated total reflection (ATR) results show both hydrogen and oxygen related IR modes in the samples which can be used to explain the PL effect.

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Zhang, Xiangzhe, Renyan Zhang, Xiaoming Zheng, Yi Zhang, Xueao Zhang, Chuyun Deng, Shiqiao Qin et Hang Yang. « Interlayer Difference of Bilayer-Stacked MoS2 Structure : Probing by Photoluminescence and Raman Spectroscopy ». Nanomaterials 9, n^o 5 (24 mai 2019) : 796. http://dx.doi.org/10.3390/nano9050796.

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This work reports the interlayer difference of exciton and phonon performance between the top and bottom layer of a bilayer-stacked two-dimensional materials structure (BSS). Through photoluminescence (PL) and Raman spectroscopy, we find that, compared to that of the bottom layer, the top layer of BSS demonstrates PL redshift, Raman E 2 g 1 mode redshift, and lower PL intensity. Spatial inhomogeneity of PL and Raman are also observed in the BSS. Based on theoretical analysis, these exotic effects can be attributed to substrate-coupling-induced strain and doping. Our findings provide pertinent insight into film–substrate interaction, and are of great significance to researches on bilayer-stacked structures including twisted bilayer structure, Van der Waals hetero- and homo-structure.

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Bleisteiner, Bernd. « Raman- und PL-Spektroskopie an Kohlenstoffnanoröhren ». Nachrichten aus der Chemie 55, n^o 4 (avril 2007) : 430–32. http://dx.doi.org/10.1002/nadc.200747533.

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Gu, Kai, Ming Sun et Yang Zhang. « Tip-Enhanced Raman Spectroscopy Based on Spiral Plasmonic Lens Excitation ». Sensors 22, n^o 15 (28 juillet 2022) : 5636. http://dx.doi.org/10.3390/s22155636.

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In this study, we proposed the idea of replacing the traditional objective lens in bottom-illumination mode with a plasmonic lens (PL) to achieve tip-enhanced Raman spectroscopy (TERS). The electric field energy of surface plasmon polaritons (SPPs) of the spiral PL was found to be more concentrated at the focal point without any sidelobe using the finite-difference time domain (FDTD) method compared with that of a symmetry-breaking PL. This property reduces far-field background noise and increases the excitation efficiency of the near-field Raman signal. The disadvantage of only the near-field Raman scattering of samples at the center of the structure being detected when using an ordinary PL in TERS is overcome by using our proposed method of changing only the polarization of the incident light.

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Han, Tao, Hongxia Liu, Shulong Wang, Shupeng Chen, Kun Yang et Zhandong Li. « Synthesis and Spectral Characteristics Investigation of the 2D-2D vdWs Heterostructure Materials ». International Journal of Molecular Sciences 22, n^o 3 (27 janvier 2021) : 1246. http://dx.doi.org/10.3390/ijms22031246.

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Due to the attractive optical and electrical properties, van der Waals (vdWs) heterostructures constructed from the different two-dimensional materials have received widespread attention. Here, MoS2/h-BN, MoS2/graphene, WS2/h-BN, and WS2/graphene vdWs heterostructures are successfully prepared by the CVD and wet transfer methods. The distribution, Raman and photoluminescence (PL) spectra of the above prepared heterostructure samples can be respectively observed and tested by optical microscopy and Raman spectrometry, which can be used to study their growth mechanisms and optical properties. Meanwhile, the uniformity and composition distribution of heterostructure films can also be analyzed by the Raman and PL spectra. The internal mechanism of Raman and PL spectral changes can be explained by comparing and analyzing the PL and Raman spectra of the junction and non-junction regions between 2D-2D vdWs heterostructure materials, and the effect of laser power on the optical properties of heterostructure materials can also be analyzed. These heterostructure materials exhibit novel and unique optical characteristics at the stacking or junction, which can provide a reliable experimental basis for the preparation of suitable TMDs heterostructure materials with excellent performance.

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Li, Chun Ping, Jian Zhang, Hua Min Yu et Li Zhong Zhang. « Raman and Photoluminescence Properties of ZnO Nanorods with Wurtzite Structure ». Key Engineering Materials 538 (janvier 2013) : 50–53. http://dx.doi.org/10.4028/www.scientific.net/kem.538.50.

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Raman, resonant Raman and photoluminescence (PL) properties of ZnO nanorods that produced by simple solution chemical process are reported in this paper. The transmission electron microscopy measurements show that the obtained ZnO nanorods have well-proportioned distribution with diameters about 30 nm, and the maximal lengths up to more than 2.2 μm. The micro-Raman and resonant Raman spectrum of nanorods show the obvious differences from that of the commercial bulk phase ZnO samples. The PL with intense UV emission indicates the good quality of the obtained ZnO nanorods.

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Thèses sur le sujet "Raman/PL"

Dan'ко, V. A., T. E. Grinenko, V. A. Yukhimchuk, P. E. Shepeliavyi, K. V. Michailovska et I. Z. Indutnyi. « Raman and PL investigation of light-emitting NC-Si-SiOx nanostructures ». Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20635.

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Mahmoudi, Aymen. « Propriétés électroniques des dichalcogénures bi-dimensionnels de métaux de transition ». Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP106.

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Le sujet de cette thèse s'inscrit dans la thématique des matériaux bidimensionnels (2D) d'épaisseur atomique. L'étude des propriétés optiques et électroniques des hétérostructures hybrides à base de dichalcogénures de métaux de transition (TMD) MX₂ (M = Mo, W ; X = S, Se, Te) est aujourd'hui considérée avec attention en raison de futures applications et d'études plus fondamentales. Plus que leurs propriétés physiques intrinsèques, en configuration multicouche, ces matériaux offrent des phénomènes physiques prometteurs tels que la modulation de la valeur de la bande interdite, la ferroélectricité pour des configurations cristallines spécifiques, etc. En particulier, ce travail se consacre aux hétérostructures hybrides à base de diséléniure de tungstène (WSe₂) sur des substrats de graphène et de phosphate de gallium (GaP). En mettant en œuvre des techniques de microscopie et de spectroscopie telles que la spectroscopie Raman et la spectroscopie de photoémission résolue en angle (ARPES), une étude des propriétés électroniques, optiques et structurelles d'hétérostructures composées de plusieurs matériaux 2D a été réalisée afin de fournir une meilleure compréhension de ces systèmes émergents. Par conséquent, les premières mesures directes de la structure de bande électronique de la phase rhomboédrique de la structure bicouche de WSe₂ déposée sur un substrat 2D de graphène sont présentées dans ce manuscrit. La croissance directe de ce matériau 2D sur un substrat 3D de GaP a été étudiée pour plusieurs épaisseurs. Ces travaux ont permis d'identifier l'effet de la nature de la phase cristalline ainsi que la méthode de croissance sur les structures de bandes électroniques, ce qui permet une meilleure compréhension de ces systèmes émergents
The subject of this thesis is two-dimensional (2D) materials of atomic thickness. The study of the optical and electronic properties of hybrid heterostructures based on MX₂ transition metal dichalcogenides (TMDs) (M = Mo, W; X = S, Se, Te) is now being carefully considered with a view to future applications and more fundamental studies. Beyond their intrinsic physical properties, in multilayer configurations, these materials offer promising physical phenomena such as modulation of bandgap values, ferroelectricity for specific crystal configurations, and so on. In particular, this work focuses on hybrid heterostructures based on tungsten diselenide (WSe₂) on graphene and gallium phosphate (GaP) substrates. Using microscopy and spectroscopy techniques such as Raman spectroscopy and angle-resolved photoemission spectroscopy (ARPES), we investigated the electronic, optical, and structural properties of heterostructures composed of several 2D materials to better understand these emerging systems. Accordingly, the first direct measurements of the electronic band structure of the rhombohedral phase of the WSe₂ bilayer structure deposited on a 2D graphene substrate are presented in this manuscript. The direct growth of this 2D material on a 3D GaP substrate has been studied for several thicknesses. This work has enabled us to identify the effect of the nature of the crystalline phase and the growth method on the electronic band structures, providing a better understanding of these emerging systems

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Ndong, Gerald. « Applications de la spectroscopie Raman et photoluminescence polarimétriques à la caractérisation des contraintes dans les structures semi-conductrices à base de silicium, germanium et d'arséniure de gallium ». Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00985208.

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De nos jours, l'augmentation des performances et la réduction des dimensions des composants microélectroniques ou optiques constituant les systèmes électroniques ou optroniques nécessite des techniques de caractérisation non destructrices, capables de sonder des micro- et nanoobjets. C'est dans cette optique que s'inscrivent les techniques de spectroscopie Raman et photoluminescence, capables de caractériser localement les contraintes mécaniques, introduites dans les dispositifs à semi-conducteurs actuels afin d'accroître leurs performances. Ce travail de thèse aborde deux objectifs, l'élargissement des capacités du spectromètre Raman polarimétrique comprenant l'ajout d'un module de détection du signal de luminescence et l'application des techniques et méthodologies développées à la caractérisation des contraintes dans des structures semiconductrices à base de silicium, germanium et arséniure de gallium. Après une étude expérimentale des paramètres pertinents, la dépolarisation, le retard et le dichroïsme, nécessaire afin de combiner le spectromètre Raman " classique " et un polarimètre, nous avons montré que l'étalonnage d'un tel système dépend de la longueur d'onde de la source d'excitation, ainsi que de la nature de la diffusion considérée (Raman ou Rayleigh). Au titre des applications de la technique, nous avons mesuré des contraintes mécaniques dans des nanolignes de silicium (15 nm d'épaisseur) et des microlignes de germanium grâce à la méthodologie de mesure développée. Les résultats obtenus ont été également modélisés analytiquement afin de mettre en évidence la physique des phénomènes observés. Ainsi, nous avons montré qu'il est possible d'amplifier le signal Raman dans les nanolignes de silicium grâce à la gestion appropriée des polarisations des rayonnements incident et diffusé. La mise en place de la technique de photoluminescence avec le contrôle des états de polarisation, rajoutée à la spectroscopie Raman, nous a permis d'étendre le champ de mesure des contraintes mécaniques dans les structures semiconductrices. Actuellement, grâce à cette technique, nous sommes capables de mesurer des efforts résiduels de l'ordre de 20 MPa, ce qui est au-delà des capacités de la spectroscopie Raman " conventionnelle " essentiellement limitée par la résolution spectrale.

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Cherkouk, Charaf. « Östrogennachweis in wässrigen Lösungen mit Hilfe Silzium-basierter Lichtemitter ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-62465.

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In dieser Arbeit wurde ein Sensorkonzept mit Hilfe der Si-basierten Lichtemitter (MOSLED) zum Östrogennachweis in wässrigen Lösungen entwickelt. Das Sensorkonzept basiert auf einer direkten Fluoreszenzanalyse und besteht aus der Anordnung der Bio-Komponenten und dem Verfahren zu ihrer Herstellung sowie dem eigentlichen Meßverfahren. Die Anordnung besteht aus drei Teilen: die Funktionalisierung der MOSLED-Oberfläche, die Immobilisierung des hER_-Rezeptors und die Herstellung der Referenzlösung. Den Schwerpunkt dieser Arbeit bildet die Ausführung dieser drei Teile. Die Funktionalisierung der SiO2-Oberfläche der MOSLED wurde mit Hilfe eines im Rahmen dieser Arbeit entwickelten SSC (Spraying Spin Coating)- Verfahrens realisiert. Die Ausgangsmaterialien dieses Verfahrens sind organofunktionelle Silangruppen mit drei unterschiedlichen funktionellen Gruppen, nämlich die Amino-, Carboxyl- und die Thiolgruppen. Die Optimierung dieser Methode erfolgte mittels der zwei Silangruppen APMS ((3-Aminopropyl)trimethoxysilane und Triamino-APMS (N-[3-(Trimethoxysilyl)propyl]ethylenediamine mit der gleichen Molekülstruktur, aber mit einer unterschiedlichen Anzahl an funktionellen Gruppen. Diese Resultate wurden mit in der Literatur beschriebenen Verfahren verglichen. Die Optimierung der SSC-Methode wurde zuerst auf einfache SiO2-Oberflächen und dann auf der Oberfläche der MOSLED angewendet. Die Proben wurden mit Hilfe üblicher Methoden der Oberflächenphysik- wie FTIR-, Raman- und XPS-Spektroskopie untersucht. Die Oberflächenrauhigkeit wurde mittels AFM-Spektroskopie ermittelt, deren Aufnahmen eine glatte Oberfläche bei den mit der SSC-Methode silanisierten Proben zeigen. Während die Hydrophobizität der funktionalisierten SiO2-Oberflächen zunimmt, sinkt dabei die Oberflächenenergie, welche die Anbindung eines hER_-Rezeptors mit großer Bindungsenergie begünstigt. Zur Immobilisierung des hER_-Rezeptors wurde dieser erst an das Hüllenmolekül des QDots R-655-Farbstoffs gebunden und anschließend an der SSC-silanisierten SiO2-Oberflächen adsorbiert. Der Anteil der immobilisierten Rezeptoren wurde mittels PL-Messung kontrolliert. Eine andere Immobilisierungstrategie des hER_-Rezeptors an die SiO2-Oberfläche kann mit Hilfe eines Aminosäure-Derivates um den Rezeptor realisiert werden. Eine Adsorption der Lysinaminosäure an die SSC-APMS silanisierten SiO2- Oberflächen als Funktion des pH-Wertes wurde durchgeführt, und der Adsorbatsanteil des Lysins mittels XPS-Messung durch die Bindungsenergien der Energieniveaus C1s und N1s berechnet. Eine Referenzlösung mit QDots R800-Farbstoff markierten Östrogenmolekülen kommt zum Einsatz. Dabei wird die Position 17 des β-Estradiolmoleküls, welches mit einem N-Hydroxysuccinimide Derivat versehen ist, an das Hüllenmolekül des QDots R800-Farbstoff gebunden, sodass der Phenolring des β-Estradiols frei bleibt. Insbesondere ist bei den FTIR-Spektren eine nichtgebunden OH-Gruppe des β-Estradiolmoleküls gut erkennbar. Das gesamte Sensorkonzept wurde an zwei mit Östrogen mit einer Konzentration von 1mM und 1μM versetzten Wasserproben getestet. Die Anordnung der Bio-Komponenten wurde mittels PL nachgewiesen. Der Östrogennachweis wurde mit Hilfe des Ge- und Tb-basierten Lichtemitters demonstriert
A sensor concept for estrogen detection in waterish solutions by Silicon based light emitters (MOSLED) was developed. This concept is based on direct fluorescence analysis and consists of a certain arrangement of the bio- components and their fabrication methods as well as the measurements protocol, which consists of for main steps: Passing the prepared MOSLED surface by the water sample, a washing step, passing the MOSLED surface by the reference solution, and the final optical measurement. The arrangement consists of three parts: the functionalisation of the MOSLEDs surface, the immobilization of the hERff receptor und finally the fabrication of the reference solution. The focus of this work is set on the achievement of these three parts. The functionalisation of the SiO2-surface of the MOSLED was realized by means of the new developed SSC (Spraying Spin Coating) method. The chemical precursor of this method are the organofunctional silane groups with three different functional groups, namely the amino-, carboxyl-, and thiolgroups. The optimization of the procedure was investigated with two types of silane groups APMS ((3-Aminopropyl)trimethoxysilane und Triamino-APMS (N-[3-(Trimethoxysilyl)propyl]ethylenediamine), which have the same molecular structure but a different number of functional groups per molecule. These results have been compared with those of the literature. The optimization of the SSC-method was analyzed by means of standard surface science techniques like FTIR-, Raman-, and XPS-spectroscopy. The surface roughness was applied by using AFM-spectroscopy, which showed a smooth surface by the samples treated with the SSC-method. Whereas the hydrophobicity of the functionalized SiO2 surface increases, the surface energy decreases, which favours the binding of a hERff receptor with large binding energy. In order to immobilize the hERff receptor at the surface, the receptor was bound to the molecular shell of the QDots655-dye and finally adsorbed to the silanized SiO2 surfaces. The fraction of the immobilized hERff receptors was controlled via PL-measurements. Another labelling strategy to immobilize the receptor at the SiO2 surface can be realized by using the amino acid as derivate to modify the receptor. For this aim the adsorption of the lysine at silanized SiO2 surfaces was investigated as function of the pH-value. The adsorbent part of the lysine was calculated via XPS by measuring the binding energy of both energy levels C1s and N1s . The reference solution with QDots800-dye marked estrogen molecules was used. The optimal binding was achieved by attaching the molecular shell of the QDots 800-dye to position 17 of the β-Estradiol molecule, which contains of a N-Hydroxysuccinimid derivate so that the phenol ring of the β-Estradiol remains free. In particular the FTIR-spectra showed the non-binding OH-groups of the β-Estradiol molecule. The whole concept of the sensor was tested at two water samples containing estrogen in a concentration of 1mM and 1μM. The adjustment of the Biokomponents was proven by PL, and the estrogen detection was demonstrated by using the Ge- and Tb-based light emitters

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Bandyopadhyay, Avra Sankar. « Light Matter Interactions in Two-Dimensional Semiconducting Tungsten Diselenide for Next Generation Quantum-Based Optoelectronic Devices ». Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1752376/.

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In this work, we explored one material from the broad family of 2D semiconductors, namely WSe2 to serve as an enabler for advanced, low-power, high-performance nanoelectronics and optoelectronic devices. A 2D WSe2 based field-effect-transistor (FET) was designed and fabricated using electron-beam lithography, that revealed an ultra-high mobility of ~ 625 cm2/V-s, with tunable charge transport behavior in the WSe2 channel, making it a promising candidate for high speed Si-based complimentary-metal-oxide-semiconductor (CMOS) technology. Furthermore, optoelectronic properties in 2D WSe2 based photodetectors and 2D WSe2/2D MoS2 based p-n junction diodes were also analyzed, where the photoresponsivity R and external quantum efficiency were exceptional. The monolayer WSe2 based photodetector, fabricated with Al metal contacts, showed a high R ~502 AW-1 under white light illumination. The EQE was also found to vary from 2.74×101 % - 4.02×103 % within the 400 nm -1100 nm spectral range of the tunable laser source. The interfacial metal-2D WSe2 junction characteristics, which promotes the use of such devices for end-use optoelectronics and quantum scale systems, were also studied and the interfacial stated density Dit in Al/2D WSe2 junction was computed to be the lowest reported to date ~ 3.45×1012 cm-2 eV-1. We also examined the large exciton binding energy present in WSe2 through temperature-dependent Raman and photoluminescence spectroscopy, where localized exciton states perpetuated at 78 K that are gaining increasing attention for single photon emitters for quantum information processing. The exciton and phonon dynamics in 2D WSe2 were further analyzed to unveil other multi-body states besides localized excitons, such as trions whose population densities also evolved with temperature. The phonon lifetime, which is another interesting aspect of phonon dynamics, is calculated in 2D layered WSe2 using Raman spectroscopy for the first time and the influence of external stimuli such as temperature and laser power on the phonon behavior was also studied. Furthermore, we investigated the thermal properties in 2D WSe2 in a suspended architecture platform, and the thermal conductivity in suspended WSe2 was found to be ~ 1940 W/mK which was enhanced by ~ 4X when compared with substrate supported regions. We also studied the use of halide-assisted low-pressure chemical vapor deposition (CVD) with NaCl to help to reduce the growth temperature to ∼750 °C, which is lower than the typical temperatures needed with conventional CVD for realizing 1L WSe2. The synthesis of monolayer WSe2 with high crystalline and optical quality using a halide assisted CVD method was successfully demonstrated where the role of substrate was deemed to play an important role to control the optical quality of the as-grown 2D WSe2. For example, the crystalline, optical and optoelectronics quality in CVD-grown monolayer WSe2 found to improve when sapphire was used as the substrate. Our work provides fundamental insights into the electronic, optoelectronic and quantum properties of WSe2 to pave the way for high-performance electronic, optoelectronic, and quantum-optoelectronic devices using scalable synthesis routes.

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Wu, Gwo Tswin, et 吳國存. « Raman Spectroscopic and PL study of Wurtzite Structure Semiconductor ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/88118733130146751769.

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碩士
國立臺灣師範大學
物理學系
93
We get two InN samples from Cornell university and measure their optics characteristic.On the other hand, we study the GaN nanowires and ZnO nanorods, which be able to learn crack these energy bandgap in 3.2eV to 3.4eV from information at document, lie in ultraviolet ray range, one that is with InN be able to crack, 0.7eV- 0.8eV, lying in the infrared light district to happen it is two extremes, therefor we compared its optics nature characteristic. In this thesis, we are prior to examine the photoluminescence of the three kinds of semiconductors to be able to know the energy bandgap, than use different wavelength laser for excitation source to measure the room temperature Ramon scattering spectrum, the laser light sources used are 325nm (He-Cd laser ), 442nm (He-Cd laser ), 488nm, 514nm (Ar-ion laser ), 633nm (He-Ne laser ) and 785nm (solid-state laser ), respectively, to investigate the A1(LO) phonon mode of Raman spectra. We observed that the A1(LO) phonon mode was shifted to their energy bandgap. Wu consider this effect cause with defect and impurity.

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Lo, Shih-Chiech, et 羅士傑. « Strain analysis of InN nano-dots by Raman and X-ray and ��{PL measurements ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/67800179908537670060.

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碩士
國立交通大學
電子物理系所
94
In this thesis, we studied the strain and the optical properties of InN nano-dots with different dot height, which were grown at different temperature, by ��-Raman, ��-PL and X-ray diffraction measurements. The diffraction angle (2��) and the Raman E2 mode were observed to shift obviously with dot height. We found that the smaller InN dots experience the larger compressive stress in the a-b plane. The c-axis lattice constant can be calculated by X-ray diffraction angle (2��), so that the strain along c-axis was calculated and compared with recent reports. From the measured Raman E2 and the calculated strain, we attempted to determine the strain-free frequencies of E2 by interpolation. The calculated strain results of both InN epilayer and dots are reasonable. In addition to the intrinsic strain, the residual thermal strain cannot be neglected. The main cause for the residual thermal strain is the difference in the thermal expansion coefficient between film and substrate. Hence, we will analyze the effects due to intrinsic strain and thermal strain in our samples. For the blue shift of ��{PL results, we checked the quantum confinement and strain effects and found that both effects are important in our samples. Finally, we studied the GaN capping effect on InN dots. When the surface dots are covered by a cap layer, the compressive strain will be induced. Hence, the Raman shift increases that is consistent with X-ray diffraction results.

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Zenneck, Jan. « Optische Eigenschaften von verdünnten magnetischen Halbleitern auf GaN-Basis ». Doctoral thesis, 2007. http://hdl.handle.net/11858/00-1735-0000-0006-B46D-3.

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Chapitres de livres sur le sujet "Raman/PL"

Choudhary, Sumitra, Vikas Sharma, Abhishek Sharma, Ajay Kumar et Parveen Kumar. « Analyzing the Properties of Zinc Oxide (ZnO) Thin Film Grown on Silicon (Si) Substrate, ZnO/Si Using RF Magnetron Sputtering Approach ». Dans Modeling, Characterization, and Processing of Smart Materials, 297–308. IGI Global, 2023. http://dx.doi.org/10.4018/978-1-6684-9224-6.ch014.

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In this work, ZnO single layer thin film of 100 nm is deposited on a Si substrate using RF magnetron sputtering. Base pressure of 1.0×10−5 mbar, RF power of 100W at Ar flow 15 sccm and room temperature were process parameters. The average crystallite size of ZnO layer, deposited on Si substrate, using Scherrer's formula was 108.16 nm. XRD verifies the crystalline nature of ZnO with various peaks at (002), (101) and (103) planes. Using AFM technique, ZnO had an Average Surface Roughness (Ra) of 2.75 nm and RMS roughness (Rq) of 3.70 nm. From Hall measurements at room temperature, the authors determined that ZnO is a n-type semiconductor having a resistivity of 1 to 100 Ωcm. The layer's sheet resistance was 7.05×103 Ω/sq, and its resistivity was 7.05×10−2 Ωcm. The Raman spectra analysis confirmed the presence of Raman active modes in the sample, confirming the existence of certain vibrational modes. In PL spectra, an emission peak was observed at 380.30 nm, which closely resembled pure ZnO. These results collectively shows that the ZnO/Si thin films grown on Si demonstrated excellent quality.

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Actes de conférences sur le sujet "Raman/PL"

Trinh, Tai Cong, Rabindra Basnet, Vigneshwaran Chandrasekaran, Michael Pettes, Rahul Rao, Andrew Jones, Jin Hu et Han Htoon. « Optical Spectroscopy Unravels the Spin-Lattice Interplay in Doped NiPS3 Systems ». Dans CLEO : Applications and Technology, JTh2A.17. Washington, D.C. : Optica Publishing Group, 2024. http://dx.doi.org/10.1364/cleo_at.2024.jth2a.17.

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Our PL study revealed a strong suppression of the ultrasharp excitonic emission in Ni1- xMnxPS3 with the increase of Mn impurity concentration x. Additionally, the suppression of the two-magnon scattering peak under Raman spectroscopy, further highlights the intricate interplay between impurity-induced lattice distortion and the spin order of NiPS3.

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Campbell, I. H., et P. M. Fauchet. « Laser-induced degradation of GaAs ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.thkk5.

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Laser-induced degradation of GaAs bandgap photoluminescence (PL) has been reported by several workers1,2 but the physical mechanism responsible for this decrease remains unclear. The degradation is not caused by surface oxidation and it is thought to be the result of a nonradiative recombination enhanced defect reaction.1 Using in situ Raman scattering (RS) and PL we have observed significant decreases in bandgap PL and the formation of solid arsenic at the sample surface. In addition, the lattice temperature and the electron temperature of the spot being damaged have been measured by RS and PL, respectively. We present results as a function of laser power, dopant type, and density and for both capped and free GaAs surfaces.

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Rohini, Puliyasseri, et Dillibabu Sastikumar. « Synthesis and characterization of Graphite Oxide from Graphite using Nano second pulsed laser ablation in liquid ». Dans Advanced Solid State Lasers. Washington, D.C. : Optica Publishing Group, 2022. http://dx.doi.org/10.1364/assl.2022.jtu6b.17.

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Hinrichs, Karsten, Andreas Furchner et Jörg Rappich. « Optical monitoring during the electrochemical deposition of organic layers ». Dans Applied Industrial Spectroscopy. Washington, D.C. : Optica Publishing Group, 2023. http://dx.doi.org/10.1364/ais.2023.am1a.1.

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Infrared (IR) spectroscopy, Raman spectroscopy, Reflection-Anisotropy-Spectroscopy (RAS) and Photoluminescence (PL) spectroscopy are interface and thin-film-sensitive methods for optical monitoring in electrochemical cells. Film properties such as composition, structure and thickness are studied during deposition.

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Chen, Qiong, Naili Yue et Yong Zhang. « Micro-Raman/PL and Micro-LBIC studies of CZTSe materials and PV devices ». Dans 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC). IEEE, 2013. http://dx.doi.org/10.1109/pvsc.2013.6744998.

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Martin, P., R. Bisaro, C. Dua, O. Noblanc, S. L. Delage, D. Floriot, F. Lemaire, P. Galtier, J. P. Landesman et C. Brylinski. « Temperature Distributions in III-V and SiC Micro-Wave Power Transistors Using Spatially Resolved Photoluminescence and Raman-Spectrometry Mapping Respectively ». Dans ISTFA 2000. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.istfa2000p0435.

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Abstract This paper describes a new method for the mapping of local temperatures in the active region of highpower III-V semiconductor transistors for microwave applications. The measurement technique involves scanning a focused laser beam at the surface of a chip inside its package, while the photoluminescence (PL) or the Raman spectra produced are recorded sequentially for each position of the laser beam. The local temperature is deduced either from the corresponding wavelength shift of the PL (which represents changes in the band-gap due to heating) or from Raman Stokes peak shift or from the Stokes to anti-Stokes intensity ratio (which correspond to changes in optical phonon frequencies and population respectively due to heating). Results are shown both for SiC-based field effect transistors and for bipolar type transistors (heterojunction bipolar transistors – HBTs – in the GaAs/Ga1-xInxP system). A spatial resolution of 1 µm and an accuracy in the temperature determination of ± 3 °C are demonstrated, especially for the HBTs. Finally, procedures are proposed to implement the information on local operating temperatures provided by this method into thermal resistance calculations.

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Furis, M. « Spin-polarized PL and Raman Spectroscopy of Nanocrystal Quantum Dots in High Magnetic Fields ». Dans PHYSICS OF SEMICONDUCTORS : 27th International Conference on the Physics of Semiconductors - ICPS-27. AIP, 2005. http://dx.doi.org/10.1063/1.1994303.

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Shen, Ze Xiang, Jiaxu Yan, Juan Xia, Dongfei Li, Xi Yuan, Xiaofeng Fan et Lili Yang. « Stacking dependent electro and optical properties in 2D TMD by Raman/PL imaging (Conference Presentation) ». Dans Nanoimaging and Nanospectroscopy IV, sous la direction de Prabhat Verma et Alexander Egner. SPIE, 2016. http://dx.doi.org/10.1117/12.2238860.

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Leroy, E., S. Mamedov, E. Teboul, A. Whitley, D. Meyer et L. Casson. « Complementing and adding to SEM performance with the addition of XRF, Raman, CL and PL spectroscopy and imaging ». Dans Scanning Microscopy 2010, sous la direction de Michael T. Postek, Dale E. Newbury, S. Frank Platek et David C. Joy. SPIE, 2010. http://dx.doi.org/10.1117/12.864236.

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N, Nandha Kumar, Christin Jenifer A, Kathirvel D et Kanchana G. « Effect of FeCl3, CoCl3, and NiCl3 on the Properties of Sulphamic Acid Single Crystals ». Dans The Second National Conference on Emerging Materials for Sustainable Future, 102–7. Asian Research Association, 2024. http://dx.doi.org/10.54392/ara24110.

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The slow evaporation approach was used to create both pure Sulphamic single crystals and doped Sulphamic acid single crystals with FC, CC, and NC at room temperature. The orthorhombic system of their crystal structures was verified by Powder X-ray Diffraction (PXRD) analysis. Their vibrational modes were determined by spectrum analysis using Fourier Transform Infrared (FTIR) and FT-RAMAN. Studies on UV-Vis-NIR absorption were carried out to comprehend the optical behavior. The impurity on the absorption was detected at 365 nm, 395.75 nm, and 384.43 nm for pure and doped crystals, respectively, based on the PL spectra.

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