Relevant bibliographies by topics / Quantum Confinement Effect (QCE)

Academic literature on the topic 'Quantum Confinement Effect (QCE)'

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Published: 7 September 2023

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Journal articles on the topic "Quantum Confinement Effect (QCE)"

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RATH, S., A. K. DASH, S. N. SAHU, and S. NOZAKI. "QUANTUM CONFINEMENT EFFECT IN HgTe NANOCRYSTALS AND VISIBLE LUMINESCENCE." International Journal of Nanoscience 03, no. 03 (June 2004): 393–401. http://dx.doi.org/10.1142/s0219581x04002176.

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Mercury Telluride ( HgTe ) nanocrystals with a mean size of 5.35 nm have been synthesized by an electrochemical technique. Structural analysis by transmission electron microscopy and glancing angle X-ray diffraction studies indicate the presence of cubic phase HgTe nanocrystals in the deposit. Optical absorption measurements reveal two well resolved excitonic peaks around 578.5 nm and 550 nm attributed to heavy hole valence band (HVB)–conduction band (CB) and light hole valence band (LVB)–CB transitions, respectively, and suggest a band opening of bulk inverted narrow band gap HgTe as a result of strong quantum confinement effect (QCE). Visible photoluminescence (PL) of HgTe nanocrystals indicates free exciton transition around 579.5 nm as observed from the PL measurement at 300 K along with a bound exciton dominated band around 588 nm. Micro-Raman measurements at 300 K indicate the 1LO vibrational mode at 142.6 cm-1 shifted by 6 cm-1 from its standard bulk value and confirm the QCE.
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Liao, Lianxing, Kunhua Quan, Xiangshi Bin, Ruosheng Zeng, and Tao Lin. "Bandgap and Carrier Dynamic Controls in CsPbBr3 Nanocrystals Encapsulated in Polydimethylsiloxane." Crystals 11, no. 9 (September 17, 2021): 1132. http://dx.doi.org/10.3390/cryst11091132.

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Bandgap tunability through ion substitution is a key feature of lead halide perovskite nanocrystals (LHP-NCs). However, the low stability and low luminescent performance of CsPbCl3 hinder their full-color applications. In this work, quantum confinement effect (QCE) was utilized to control the bandgap of CsPbBr3 NCs instead of using unstable CsPbCl3, which possess much higher emission efficiency in blue spectra region. Studies of microstructures, optical spectra and carrier dynamics revealed that tuning the reaction temperature was an effective way of controlling the NC sizes as well as QCE. Furthermore, the obtained CsPbBr3 NCs were encapsulated in a PDMS matrix while maintaining their size distribution and quantum-confined optoelectronic properties. The encapsulated samples showed long-term air and water stability. These results provide valuable guidance for both applications of LHP-NCs and principal investigation related to the carrier transition in LHP-NCs.
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Fan, Libo, Hongwei Song, Haifeng Zhao, Guohui Pan, Lina Liu, Biao Dong, Fang Wang, et al. "CdS/Cyclohexylamine Inorganic–Organic Hybrid Semiconductor Nanofibers with Strong Quantum Confinement Effect." Journal of Nanoscience and Nanotechnology 8, no. 8 (August 1, 2008): 3914–20. http://dx.doi.org/10.1166/jnn.2008.18345.

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Inorganic–organic hybrid semiconductor nanofibers of CdS/CHA (CHA = cyclohexylamine) were successfully synthesized by a simple solvothermal method. The fibers obtained had average diameter of 20 nm and length of several micrometers. In these fibers, periodic layer-like sub-nanometer structures with thickness of ∼3 nm were identified by high-resolution transmission electron microscope (HR-TEM). The absorption of the hybrids exhibited a large blue-shift in contrast to the bulk, which was attributed to strong quantum confinement effect (QCE) induced by internal sub-nanometer structures. Pure hexagonal wurtzite CdS (H-CdS) nanorods were also obtained by extracting the CdS/CHA hybrids with dimethyl formamide (DMF). The rods obtained had average diameter of 20 nm and length of 200 nm. A CdS/CHA/polyvinyl alcohol (PVA) composite film emitting white light was prepared by spin coating.
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Iqbal, Anwar, Usman Saidu, Farook Adam, Srimala Sreekantan, Normawati Jasni, and Mohammad Norazmi Ahmad. "The Effects of Zinc Oxide (ZnO) Quantum Dots (QDs) Embedment on the Physicochemical Properties and Photocatalytic Activity of Titanium Dioxide (TiO2) Nanoparticles." Journal of Physical Science 32, no. 2 (August 25, 2021): 71–85. http://dx.doi.org/10.21315/jps2021.32.2.6.

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In this study, a detailed investigation on the effect of zinc oxide (ZnO) quantum dots (QDs) embedment on the physicochemical properties of anatase titanium dioxide (TiO2) was conducted. The highly porous nanocomposite labelled as ZQT was prepared via the sol-gel assisted hydrothermal method. The powder X-ray diffraction (XRD) analysis indicates that the average crystallite size of the ZnO QDs, anatase TiO2 (TiO2 NPs) and ZQT were 4.45 nm, 9.22 nm and 11.38 nm, respectively. Photoluminescent (PL) analysis detected the presence of defects related to TiO2, oxygen vacancies and quantum confinement effect (QCE) of the ZnO QDs in ZQT. These features enhanced the photodegradation of tetracycline (TC) under 48 watt of fluorescent light irradiation when ZQT (98.0%) was used compared to TiO2NPs (32.4%) and ZnO QDs (68.8%). The photodegradation activity was driven by O2●− followed by ●OH and h+.
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Shim, Jae Hyun, and Nam Hee Cho. "Photo- and Electroluminescence of Hydrogenated Nanocrystalline Si Prepared by Plasma Enhanced Chemical Vapor Deposition Techniques." Materials Science Forum 510-511 (March 2006): 958–61. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.958.

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We studied photoluminescence (PL) and electroluminescence (EL) properties of hydrogenated nanocystalline silicon (nc-Si:H) thin films prepared by applying the plasma enhanced chemical vapor deposition (PECVD) techniques. . A prototype of ITO/nc-Si:H/P-type Si wafer/Al EL devices was illustrated with its fundamental electrical and optical features. The nc-Si:H films exhibited PL spectra in a wavelength range of 350 ~ 700 nm with the maximum intensity at ~ 530 nm, which is attributed to quantum confinement effects (QCE) owing to the presence of nanocrystalline Si. The EL device produced EL spectra with their maximum intensity at ~ 525 nm which are similar to the PL spectra. The light emission is attributed to radiative recombination related to nanocrystalline Si contained in the hydrogenated amorphous Si (a-Si:H).
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Cao, Yunqing, Ping Zhu, Dongke Li, Xianghua Zeng, and Dan Shan. "Size-Dependent and Enhanced Photovoltaic Performance of Solar Cells Based on Si Quantum Dots." Energies 13, no. 18 (September 16, 2020): 4845. http://dx.doi.org/10.3390/en13184845.

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Recently, extensive studies have focused on exploring a variety of silicon (Si) nanostructures among which Si quantum dots (Si QDs) may be applied in all Si tandem solar cells (TSCs) for the time to come. By virtue of its size tunability, the optical bandgap of Si QDs is capable of matching solar spectra in a broad range and thus improving spectral response. In the present work, size-controllable Si QDs are successfully obtained through the formation of Si QDs/SiC multilayers (MLs). According to the optical absorption measurement, the bandgap of Si QDs/SiC MLs shows a red shift to the region of long wavelength when the size of dots increases, well conforming to quantum confinement effect (QCE). Additionally, heterojunction solar cells (HSCs) based on Si QDs/SiC MLs of various sizes are presented and studied, which demonstrates the strong dependence of photovoltaic performance on the size of Si QDs. The measurement of external quantum efficiency (EQE) reveals the contribution of Si QDs to the response and absorption in the ultraviolet–visible (UV-Vis) light range. Furthermore, Si QDs/SiC MLs-based solar cell shows the best power conversion efficiency (PCE) of 10.15% by using nano-patterned Si light trapping substrates.
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Fariborz, Amir H., and Renata Jora. "Examining a possible cascade effect in chiral symmetry breaking." Modern Physics Letters A 32, no. 02 (December 29, 2016): 1750008. http://dx.doi.org/10.1142/s0217732317500080.

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We examine a toy model and a cascade effect for confinement and chiral symmetry breaking which consists in several phase transitions corresponding to the formation of bound states and chiral condensates with different number of fermions for a strong group. We analyze two examples: regular quantum chromodynamics (QCD) where we calculate the “four quark” vacuum condensate and a preon composite model based on QCD at higher scales. In this context, we also determine the number of flavors at which the second chiral and confinement phase transitions occur and discuss the consequences.
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Kuvshinov, V. I., and E. G. Bagashov. "Evolution of Colour in QCD and Informational Approach to Quantum Measurement." Nonlinear Phenomena in Complex Systems 22, no. 4 (December 10, 2019): 330–35. http://dx.doi.org/10.33581/1561-4085-2019-22-4-330-335.

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Quantum chromodynamics (QCD) introduces the quantum characteristic of colour in order to satisfy the Pauli exclusion principle and symmetric considerations for wavefunctions of hadrons. However, the particles that possess colour charge (quarks and gluons) are not directly observed in experiment – the effect which is often referred to as confinement. Confinement of quarks and gluons represents a theoretical challenge, as the dynamics of underlying fields is non-perturbative and therefore is problematic to be described analytically. One possible way is to use non-perturbative approaches and derive analogies with other well-established branches of physics. In this work we describe the use of the method of vacuum correlators – to analyze the confinement and other non-perturbative dynamics of quarks. The discussion of the acquired results is then given on the basis of quantum information and measurement description. It is shown that the confinement of quarks might be associated with the decoherence of colour state due to the interaction of colour charges with the environment of colour fields (QCD stochastic vacuum).
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Mir, Feroz A., Owais I. Mir, and Rayees A. Zargar. "Structural, Morphological, Vibrational, Thermal and Optical Properties of ZnS Quantum Dots in the Polymer Matrix." Current Alternative Energy 3, no. 1 (November 28, 2019): 50–58. http://dx.doi.org/10.2174/2405463103666190704160914.

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<P>Background: Nanotechnology is believed to be a future for new human generations. Among different emerging materials, the Nanocomposites (NCs) would be on front line. The aim of the current study is provide a way to synthesis the ZnS-polyacrylamide NCs with emphasizes on the effect of aging in polymer on its various physical properties. </P><P> Objectives: To prepare and study the properties of ZnS-Polymer NCs with drying time in polymer matrix. </P><P> Methods: ZnS-polyacrylamide NCs samples were synthesized by adding aqueous suspension of ZnS Nanoparticles (NPs) in Sol of acrylamide: bisacrylamide copolymer. These samples were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), UV-Vis, and Photoluminescence (PL) spectroscopy. </P><P> Results: From XRD data analysis, nano phase and zinc blend structure of the material is confirmed. From SEM images, the pristine ZnS NPs show spherical morphology, and this texture is still preserved in the polymer composites. FT-IR confirms that there is strong interaction between polymer chain and ZnS NPs. The TGA results indicate that the incorporation of the NPs impacts the thermal properties of the ZnS-polymer NCs and displaying higher thermal stability than the pure polymer matrix. The optical data predicts the band gap and Quantum Confinement Effect (QCE) and reduction of ZnS NPs within the polymer matrix. These NCs show emission in blue region with decreases in intensity with drying time. </P><P> Conclusion: ZnS NPs incorporated in polyacrylamide ware prepared by copolymer technique. Structural analysis confirms zinc blend structure. The vibration spectra of composites samples predicts an interaction between different functional groups of polymer with the metal sulfide. These NCs show an enhanced thermally stability. The observed optical band show a red shift and quantum confinement effect. Size calculated by XRD and optical data shows good correlation with each other. The PL spectra of the NCs exhibits a broad blue emission with excitation (λex = 320 nm). The visible region emission could be originating from the radiative recombination involving defect states within the ZnS nanocrystals energy band.</P>
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Cetinel, A., N. Artunç, G. Sahin, and E. Tarhan. "Influence of applied current density on the nanostructural and light emitting properties of n-type porous silicon." International Journal of Modern Physics B 29, no. 15 (May 25, 2015): 1550093. http://dx.doi.org/10.1142/s0217979215500939.

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Effects of current density on nanostructure and light emitting properties of porous silicon (PS) samples were investigated by field emission scanning electron microscope (FE-SEM), gravimetric method, Raman and photoluminescence (PL) spectroscopy. FE-SEM images have shown that below 60 mA/cm 2, macropore and mesopore arrays, exhibiting rough morphology, are formed together, whose pore diameter, pore depth and porosity are about 265–760 nm, 58–63 μ m and 44–61%, respectively. However, PS samples prepared above 60 mA/cm 2 display smooth and straight macropore arrays, with pore diameter ranging from 900–1250 nm, porosity of 61–80% and pore depth between 63–69 μ m . Raman analyses have shown that when the current density is increased from 10 mA/cm 2 to 100 mA/cm 2, Raman peaks of PS samples shift to lower wavenumbers by comparison to crystalline silicon (c-Si). The highest Raman peak shift is found to be 3.2 cm -1 for PS sample, prepared at 90 mA/cm 2, which has the smallest nanocrystallite size, about 5.2 nm. This sample also shows a pronounced PL, with the highest blue shifting, of about 12 nm. Nanocrystalline silicon, with the smallest nanocrystallite size, confirmed by our Raman analyses using microcrystal model (MCM), should be responsible for both the highest Raman peak shift and PL blue shift due to quantum confinement effect (QCE).
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Dissertations / Theses on the topic "Quantum Confinement Effect (QCE)"

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Koulentianos, Dimitrios. "Quantum confinement effect in materials for solar cell applications." Thesis, Uppsala universitet, Materialteori, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-237189.

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Sun, Xiangzhong 1968. "The effect of quantum confinement on the thermoelectric figure of merit." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9308.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1999.
Includes bibliographical references (p. 161-165).
The thermoelectric figure of merit (Z) determines the usefulness of a material for thermoelectric energy conversion applications. Since the 1960's, the best thermoelectric material has been Bi2Te3 alloys, with a ZT of 1.0 at a temperature ofT = 300 K. The advancement of nano-scale technologies has opened up the possibility of engineering materials at nano-scale dimensions to achieve low-dimensional thermoelectric structures which may be superior to their bulk forms. In this thesis, I established the basis of the low dimensional thermoelectric transport principle in the Si/Si1-xGex quantum well superlattice (two-dimensional) system and in the Bi quantum wire (one-dimensional) system. In bulk form, Si1_xGex is a promising thermoelectric material for high temperature applications. The Si/Si1 _xGex quantum well superlattice structures are studied based on their electronic band structures using semiclassical transport theory. Detailed subband structures are considered in an infinite series of finite height quantum wells and barriers. A significant enhancement of the thermoelectric figure of merit is expected. Based on my calculations, experimental studies are designed and performed on MBE grown Si/Sii -xGex quantum well superlattice structures. The experimental results are found to be consistent with theoretical predictions and indicate a significant enhancement of Z within the quantum wells over bulk values. The bismuth quantum wire system is a one-dimensional (ID) thermoelectric system. Bismuth as a semimetal is not a good thermoelectric material in bulk form becamm of the approximate cancellation between the electron and hole contributions to the Seebeck coefficient. However, quantum confinement can be introduced by making Bi nanowires to yield a ID semiconductor. ID transport properties are calculated along the principal crystallographic directions. By carefully tailoring the Bi wire size and carrier concentration, substantial enhancement in Z is expected. A preliminary experimental study of Bi nanowire arrays is also presented.
by Xiangzhong Sun.
Ph.D.
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Reynolds, Bryan. "Electronic Transport Properties of Nanonstructured Semiconductors: Temperature Dependence and Size Effects." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1463130513.

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Li, Li. "Study of Metal-Insulator-Metal Diodes for Photodetection." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1367319217.

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Morioka, Naoya. "Fundamental Study on Carrier Transport in Si Nanowire MOSFETs with Smooth Nanowire Surfaces." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188599.

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Ribeiro, Márcia. "Estudo das propriedades estruturais e ópticas em materiais nanoestruturados a base de silício." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-20072009-155431/.

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Esta tese de doutorado tem por objetivo aprofundar as pesquisas realizadas no mestrado, a saber, da caracterização e estudo das propriedades estruturais e ópticas de filmes de oxinitreto de silício (SiOxNy:H) ricos em silício depositados pela técnica de deposição química a vapor assistida por plasma a baixa temperatura (PECVD). Os resultados obtidos no mestrado indicaram que os filmes de SiOxNy:H ricos em silício apresentam emissão luminescente na faixa do visível cuja intensidade e freqüência de emissão estão em correlação com o excesso de silício. Os resultados sugeriram que o excesso de silício na matriz do SiOxNy:H estava disposto na forma de aglomerados de silício de dimensões nanométricas responsáveis por efeitos de tamanho quântico bem como a estados radiativos na interface dos aglomerados com a matriz isolante. Neste trabalho a fim de avaliar o efeito da separação de fases, do tamanho quântico, e da interface, foram produzidos sistemas nanoestruturados a base de silício com total e parcial separação de fases para caracterizar e analisar suas propriedades ópticas e estruturais e compará-las com as dos filmes ricos em silício. Assim foram produzidas multicamadas de a-Si:H de poucos nanômetros de espessura com materiais dielétricos. Em algumas destas multicamadas foi promovida a mistura parcial das camadas por meio de bombardeamento iônico. O estudo nas estruturas de multicamadas permitiu caracterizar e analisar as propriedades estruturais e ópticas de materiais nanoestruturados com total e parcial separação de fases para posteriormente contrastá-los com as características dos filmes de oxinitreto de silício ricos em silício. A fim de analisar a influência da interface nas propriedades ópticas destes sistemas as multicamadas foram fabricadas com dois dielétricos diferentes: o óxido de silício e o ni treto de silício. A espessura das camadas dielétricas foi mantida fixa entanto que a das camadas de silício foi variada para avaliar efeitos de confinamento no silício. A caracterização foi feita utilizando técnicas de absorção óptica no UV-Vis, absorção no infravermelho (FTIR), espectroscopia Raman, fotoluminescência (PL), espectroscopia de absorção de raios X próximos 7 à borda do silício (XANES), e microscopia eletrônica de transmissão de alta resolução (HRTEM). Da análise dos resultados concluiu-se que o confinamento é fundamental para a existência da emissão luminescente embora o tipo de interface influencie a energia e a intensidade da emissão. A análise comparativa com as multicamadas permitiu verificar que os filmes de oxinitreto de silício ricos em silício apresentam, separação parcial de fases já como depositados, os tratamentos térmicos promovem a segregação do silício aumentando conseqüentemente a separação de fases.
The aim of this doctorate thesis is to enhance the knowledge in the research conducted along the Master degree based on the characterization and study of the structural and luminescent properties of silicon rich silicon oxynitride films (SiOxNy:H) deposited at low temperature by Plasma Enhanced Chemical Vapor Deposition (PECVD). The results of this study indicated that silicon rich SiOxNy:H films present luminescence in the visible spectra range with intensity and frequency in correlation with the silicon excess. The results suggested that the silicon excess in the SiOxNy:H matrix is confined in nanometric silicon clusters responsible for the to quantum size effects as well as for radiactive states at the interface of the silicon clusters with the insulating matrix. In the present work in order to evaluate the effect of phase separation, quantum size and interface effects si licon based nanostructured systems presenting total and partial phase separation were produced and their structural and optical properties were characterized in order to correlate them with the silicon rich films ones. In this way multilayers with few nanometers thick a-Si layers with dielectric materials were produced. The mixture of the layers was promoted by ion bombardment in some of these multilayers. The study of these structures permitted the characterization of structural and optical properties of materials with total and partial phase separation with the purpose of comparing them to the silicon-rich silicon oxynitride films characteristics. In order to analyze the interface influence in the optical properties, multilayers systems with two different dielectric materials, silicon oxide and silicon nitride, were fabricated. The dielectric layer thickness was kept constant while the silicon layer was varied in order to study the confinement effect. The characterization was done utilizing UV-Vis optical absorption, infrared absorption (FTIR), Raman spectroscopy, Photoluminescence (PL), X-ray absorption near edge spectroscopy (XANES) and high-resolution transmission electron microscopy (HRTEM) techniques. From the results analysis it was concluded that confinement is essent ial for the existence of luminescent 9 emission although the type of interface also influences the energy and intensity of the emission. The comparative analysis with the multilayers permitted to verify that the silicon-rich silicon oxynitride films present, as deposited, partial phase separation and that the thermal treatments promotes silicon aggregation thus increasing the phase separation.
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Mouillon, Alexandre. "Couples de spin-orbite dans une couche de métal ferromagnétique ultramince comprise entre deux oxydes : confinement quantique et effet Rashba." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY034.

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Mis en évidence expérimentalement au début des années 2010, les couples de spin-orbite (SOTs) ont très rapidement suscité un très fort intérêt dans la communauté du magnétisme et de l'électronique de spin. En effet, ils permettent,dans un empilement de type métal lourd / métal ferromagnétique / oxyde (HM/FM/Ox), de manipuler l'aimantation de la couche ferromagnétique (FM) en injectant un courant dans le plan des couches. En remarquant que la bicouche FM/Ox correspond à la moitié d'un empilement typique utilisé dans les cellules mémoires de types MRAM (Magnetic Random Access Memory, mémoire magnétique à accès aléatoire), on comprend que ce mécanisme est très intéressant pour l'écriture de la couche libre de ces cellules. En effet, le courant d'écriture ne traverse plus la barrière tunnel, ce qui répond naturellement à certaines limitations des MRAM actuelles. L'interprétation physique de ces phénomènes s'est cependant révélée particulièrement complexe. Ces couples ont deux composantes, généralement appelée "Field-like", FL, et "Damping-like", DL. Si dans un premier temps, les études théoriques ont prédit que la composante DL provenait principalement d'un effet de volume dans la couche HM,et que la composante FL provenait principalement d'un effet d'interface, des études expérimentales plus récentes ont montré qu'il n'était pas si simple de séparer ces deux contributions.Dans ce travail de thèse, nous avons choisi une approche originale permettant de n'étudier qu'une seule des deux contributions. Pour ce faire, nous avons choisi de nous concentrer sur la contribution interfaciale en étudiant des échantillons de types Ox1/FM/Ox2. Nous avons ainsi pu mettre en évidence dans ces empilements la présence de SOTs ce qui n'était textit{a priori} pas si évident dans une structure ne contenant pas de métal lourd et présentant de surcroît une forte symétrie. D'autre part, nous avons pu montrer que seule la composante FL de ces couples était présente. Le comportement inattendu de ce FL-SOT en fonction de l'épaisseur de la couche FM, nous a conduit à proposer un modèle basé sur la combinaison d'un effet interfacial de type Rahsba et d'un effet de confinement quantique dû à la très faible épaisseur de matériau conducteur dans ces empilements
Experimentally demonstrated in the early 2010's, spin-orbite torques (SOTs) very quickly generated a very strong interest in the magnetism and spin electronics community. Indeed, they allow, in a heavy metal / ferromagnetic metal / oxide (HM/FM/Ox) multilayer, to manipulate the magnetization of the ferromagnetic layer (FM) by injecting an in-plane current. Noting that the FM/Ox bilayer corresponds to half of a typical stack used in MRAM memory cells (Magnetic Random Access Memory), we understand that this mechanism is very interesting for writing the free layer of these cells. Indeed, the writing current no longer crosses the tunnel barrier, which naturally responds to some of the limitations of current MRAMs. However, the physical interpretation of these phenomena has proved to be particularly complex. These torques have two components, generally called "Field-like", FL, and "Damping-like", DL. While initially, theoretical studies predicted that the DL component was mainly due to a volume effect in the HM layer, and the FL component was mainly due to an interface effect, more recent experimental studies have shown that it is not so simple to separate these two contributions.In this thesis work, we have chosen an original approach that allows us to study only one of the two contributions. To do so, we have chosen to focus on the interfacial contribution by studying Ox1/FM/Ox2 samples. We were thus able to highlight in these stacks the presence of SOTs, which was not so obvious in a structure that did not contain heavy metal and also had a strong symmetry. On the other hand, we were able to show that only the FL component of these couples was present. The unexpected behaviour of this FL-SOT as a function of the thickness of the FM layer led us to propose a model based on the combination of a Rahsba interfacial effect and a quantum confinement effect due to the very thin thickness of conductive material in these multilayers
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Yoshioka, Hironori. "Fundamental Study on Si Nanowires for Advanced MOSFETs and Light-Emitting Devices." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/123341.

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Ramanathan, Sivakumar. "Optical and electrical properties of compound and transition metal doped compound semiconductor nanowires." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1667.

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Nanotechnology is the science and engineering of creating functional materials by precise control of matter at nanometer (nm) length scale and exploring novel properties at that scale. It is vital to understand the quantum mechanical phenomena manifested at nanometer scale dimensions since that will enable us to precisely engineer quantum mechanical properties to realize novel device functionalities. This dissertation investigates optical and electronic properties of compound and transition metal doped compound semiconductor nanowires with a view to exploiting them for a wide range of applications in semiconductor electronic and optical devices. In this dissertation work, basic concepts of optical and electronic properties at low dimensional structures will be discussed in chapter 1. Chapter 2 discusses the nanofabrication technique employed to fabricate highly ordered nanowires. Using this method, which is based on electrochemical self-assembly techniques, we can fabricate highly ordered and size controlled nanowires and quantum dots of different materials. In Chapter 3, we report size dependent fluorescence spectroscopy of ZnSe and Mn doped ZnSe nanowires fabricated by the above method. The nanowires exhibit blue shift in the emission spectrum due to quantum confinement effect, which increases the effective bandgap of the semiconductor. We found that the fluorescence spectrum of Mn doped ZnSe nanowires shows high luminescence efficiency, which seems to increase with increasing Mn concentration. These results are highly encouraging for applications in multi spectral displays. Chapter 4 investigates field emission results of highly ordered 50 nm tapered ZnO nanowires that were also fabricated by electrochemical self-assembly. Subsequent to fabrication, the nanowires tips are exposed by chemical etching which renders the tips conical in shape. This tapered shape concentrates the electric field lines at the tip of the wires, and that, in turn, increases the emission current density while lowering the threshold field for the onset of field emission. Measurement of the Fowler-Nordheim tunneling current carried out in partial vacuum indicates that the threshold electric field for field emission in 50-nm diameter ZnO nanowires is 15 V/µm. In this study we identified the key constraint that can increase the threshold field and reduce emission current density. In Chapter 5 we report optical and magnetic measurement of Mn-doped ZnO nanowires. Hysterisis measurements carried out at various temperatures show a ferromagnetic behavior with a Curie temperature of ~ 200 K. We also studied Mn-doping of the ZnO nanowires. The room temperature fluorescence spectroscopy of Mn-doped ZnO nanowires shows a red-shift in the spectra compared to the undoped ZnO nanowires possibly due to strain introduced by the dopants in the nanowires. Finally, in Chapter 6, we report our study of the ensemble averaged transverse spin relaxation time (T2*) in InSb thin films and nanowires using electron spin resonance (ESR) measurement. Unfortunately, the nanowires contained too few spins to produce a detectable signal in our apparatus, but the thin films contained enough spins (> 109/cm2) to produce a measurable ESR signal. We found that the T2* decreases rapidly with increasing temperature between 3.5 K and 20 K, which indicates that spin-dephasing is primarily caused by spin-phonon interactions.
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Hory, Marie Anne. "Contribution à l'étude de la luminescence du silicium poreux : analyse infrarouge de la passivation de surface et effets de la polarisation électrique." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10150.

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Les etudes presentees dans ce manuscrit portent sur la photo- (pl) et l'electro-luminescence (el) de couches de silicium poreux obtenu par attaque electrochimique de substrat de silicium monocristallin. La premiere partie presente les principales caracteristiques du materiau et la description de ses proprietes de luminescence accompagnee des differents modeles avances pour en expliquer les mecanismes, en s'attachant tout particulierement a celui du confinement quantique des porteurs dans les cristallites qui forment la couche poreuse, qui est le plus generalement retenu. La deuxieme partie decrit les differents montages experimentaux permettant la formation des couches poreuses et leurs caracterisations. Dans une troisieme partie, nous presentons les resultats obtenus lors de l'etude par spectroscopie infrarouge de l'influence des especes presentes en surface des cristallites de silicium sur la pl de la couche poreuse. Nous montrons que la desorption de l'hydrogene present en surface apres formation du materiau s'accompagne d'une diminution de l'intensite de pl. L'analyse de la composition chimique d'une couche poreuse oxydee electrochimiquement nous permet de mettre en evidence la conservation de la passivation par l'hydrogene au cours de ce traitement et de confirmer que l'augmentation du rendement quantique de l'emission associee a l'oxydation electrochimique peut etre attribuee a une meilleure localisation des porteurs photogeneres dans les cristallites. La quatrieme partie est consacree aux effets d'une polarisation electrique sur les phenomenes de luminescence. Ce travail a ete mene sur des couches nanoporeuses formees sur substrat de type n, polarisees par l'intermediaire d'un contact electrolytique. On observe une extinction selective, progressive (mais reversible) de la pl quand la polarisation cathodique est augmentee. Parallelement, l'el observee en presence d'une espece oxydante dans l'electrolyte subit un deplacement spectral vers le bleu. L'etude detaillee des differentes caracteristiques de ces deux phenomenes nous permet de montrer qu'ils resultent de l'injection selective des electrons depuis le substrat dans les cristallites de plus en plus confinees au fur et a mesure que la polarisation augmente. On verifie par ailleurs que ce caractere selectif disparait progressivement au cours de l'oxydation electrochimique de la couche poreuse. L'extinction de la pl et de l'el sous forte polarisation cathodique peut etre attribuee a la recombinaison non radiative des porteurs de charges par un mecanisme de type auger
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Books on the topic "Quantum Confinement Effect (QCE)"

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1941-, Kuchar F., Heinrich H, Bauer G. 1942-, and Österreichische Physikalische Gesellschaft, eds. Localization and confinement of electrons in semiconductors: Proceedings of the sixth international winter school, Mauterndorf, Austria, February 19-23, 1990. Berlin: Springer-Verlag, 1990.

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Li, Jing, and Xiao-Ying Huang. Nanostructured crystals: An unprecedented class of hybrid semiconductors exhibiting structure-induced quantum confinement effect and systematically tunable properties. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533053.013.16.

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This article describes the structure-induced quantum confinement effect in nanostructured crystals, a unique class of hybrid semiconductors that incorporate organic and inorganic components into a single-crystal lattice via covalent (coordinative) bonds to form extended one-, two- and three-dimensional network structures. These structures are comprised of subnanometer-sized II-VI semiconductor segments (inorganic component) and amine molecules (organic component) arranged into perfectly ordered arrays. The article first provides an overview of II-VI and III-V semiconductors, II-VI colloidal quantum dots, inorganic-organic hybrid materials before discussing the design and synthesis of I-VI-based inorganic-organic hybrid nanostructures. It also considers the crystal structures, quantum confinement effect, bandgaps, and optical properties, thermal properties, thermal expansion behavior of nanostructured crystals.
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Heinrich, H., and F. Kuchar. Localization and Confinement of Electrons in Semiconductors: Proceedings of the 6th International Winter School Mauterndorf, Austria, February 19-23, (Springer Series in Solid-State Sciences). Springer, 1991.

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Roditchev, D., T. Cren, C. Brun, and M. V. Milošević. Local-Scale Spectroscopic Studies of Vortex Organization in Mesoscopic Superconductors. Edited by A. V. Narlikar. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780198738169.013.2.

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This article examines the vortex matter of mesoscopic superconductors with numerous vortex states that do not exist in bulk superconductors. Using scanning tunneling microscopy/spectroscopy, it investigates the organization of vortex cores at different levels of confinement. The article begins with a discussion of the basic properties of quantum vortices in superconductors and experimental requirements for studying vortex confinement phenomena. It then considers the effect of sample size and shape on vortex distribution and pinning, along with the resulting ultra-dense configurations that cannot be achieved in bulk superconductors. It also describes the peculiar features of vortices in atomically thin superconductors having mixed Abrikosov–Josephson vortices.
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Book chapters on the topic "Quantum Confinement Effect (QCE)"

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Girvin, S. M., and A. H. MacDonald. "Off-Diagonal Long-Range Order, Oblique Confinement, and the Fractional Quantum Hall Effect." In Quantum Hall Effect: A Perspective, 261–64. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-010-9709-3_31.

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Wei, H. P., D. C. Tsui, and A. M. M. Pruisken. "Metal-Insulator Transition in the Integer Quantum Hall Effect." In Localization and Confinement of Electrons in Semiconductors, 154–61. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84272-6_17.

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Eisenstein, J. P. "New Condensed States in the Fractional Quantum Hall Effect." In Localization and Confinement of Electrons in Semiconductors, 183–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84272-6_20.

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Yu, Peter Y., and Manuel Cardona. "Effect of Quantum Confinement on Electrons and Phonons in Semiconductors." In Fundamentals of Semiconductors, 469–551. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/3-540-26475-2_9.

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Yu, Peter Y., and Manuel Cardona. "Effect of Quantum Confinement on Electrons and Phonons in Semiconductors." In Fundamentals of Semiconductors, 457–535. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03848-2_9.

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Yu, Peter Y., and Manuel Cardona. "Effect of Quantum Confinement on Electrons and Phonons in Semiconductors." In Fundamentals of Semiconductors, 457–535. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-662-03313-5_9.

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Yu, Peter Y., and Manuel Cardona. "Effect of Quantum Confinement on Electrons and Phonons in Semiconductors." In Fundamentals of Semiconductors, 469–551. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-00710-1_9.

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Akimoto, R., Y. Kinpara, and K. Akita. "Large quantum confinement effect of conduction electrons in ZnSe/BeTe type II heterostructures." In Springer Proceedings in Physics, 471–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59484-7_220.

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Fontein, P. F., J. A. Kleinen, P. Hendriks, F. A. P. Blom, J. H. Wolter, H. G. M. Lochs, F. A. J. M. Driessen, and L. J. Giling. "The Spatial Potential Distribution in GaAs/AlxGa1-xAs Heterostructures Under Quantum Hall Conditions Studied with the Linear Electro-Optic Effect." In Localization and Confinement of Electrons in Semiconductors, 162–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84272-6_18.

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Ramalingam, Gopal, Poopathy Kathirgamanathan, Ganesan Ravi, Thangavel Elangovan, Bojarajan Arjun kumar, Nadarajah Manivannan, and Kaviyarasu Kasinathan. "Quantum Confinement Effect of 2D Nanomaterials." In Quantum Dots - Fundamental and Applications. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.90140.

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Conference papers on the topic "Quantum Confinement Effect (QCE)"

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Miller, D. A. B. "Physics and applications of room temperature excitonic electroabsorption in quantum wells." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.ws1.

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Quantum well systems, where electrons and holes are confined in thin (e.g., 100-Å) layers of a narrow band gap semiconductor (e.g., GaAs) by the adjacent wider band gap semiconductor layers (e.g., GaAIAs), show several interesting optical effects. In addition to making exciton absorption resonance resolvable at room temperature, the confinement results in the quantum-confined Stark effect (QCSE)1; with electric fields perpendicular to the layers of the material, the excitonic absorption shifts by large amounts (e.g., 40 meV). This effect enables high-speed modulators of micron thickness to be made.2 It can be explained as a Stark shift of the exciton energy in which the confinement inhibits the field ionization (which normally would destroy the resonance). Shifts as large as four times the binding energy can be seen at fields corresponding to 200 times the classical ionization field. The structures can also simultaneously operate as photodetectors with photocurrent proportional to absorbed power. Since absorbed power depends on voltage (field) through the QCSE, a simple electronic circuit (e.g., a resistor and bias supply) gives optoelectronic feedback which is the principle of the self-electrooptic effect device (SEED).3 Positive feedback gives optical bistability, while with negative feedback, linearized modulation and optical level shifting are possible. These devices are compatible with diode lasers and semiconductor electronics in wavelengths, power levels, voltages, materials, and fabrication, and offer very low energy operation (e.g., –10 fJ/ square micron).
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Tada, Kunio, Shinji Nishimura, Yuen Chuen Chan, and Takuya Ishikawa. "Polarization-Independent Optical Waveguide Switch with Parabolic Potential Quantum Well." In Photonic Switching. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/phs.1991.fb3.

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Carrier confinement in semiconductor quantum wells(QWs) results in extremely large exciton binding energy and oscillator strength when compared with those of bulk crystals. Under an electric field applied perpendicular to the QW layer, the energy of the fundamental absorption edge shifts by a large amount without severe line broadening of the exciton resonance. This well-known quantum-confined Stark effect(QCSE) enables one to utilize QWs for high-speed optical waveguide modulators. Recently, not only QWs with rectangular potential shape, but also several kinds of QWs with modified potential shapes have been studied both theoretically [1,2] and experimentally [3,4], but none of them exhibit polarization-independent electric-field-induced optical effects.
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Shevchenko, Vladimir. "Quantum measurements and chiral magnetic effect." In Xth Quark Confinement and the Hadron Spectrum. Trieste, Italy: Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.171.0082.

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Lugli, Paolo, Paoli Bordone, S. Gualdi, and Stephen M. Goodnick. "Effect of phonon confinement in quantum well systems." In Semi - DL tentative, edited by Robert R. Alfano. SPIE, 1990. http://dx.doi.org/10.1117/12.20702.

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Vayssieres, Lionel. "One-dimensional confinement effect in hematite quantum rod arrays." In SPIE Optics + Photonics, edited by Lionel Vayssieres. SPIE, 2006. http://dx.doi.org/10.1117/12.678301.

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Ding, S. A., M. Ikeda, M. Fukuda, S. Miyazaki, and M. Hirose. "Quantum Confinement Effect in Self-Assembled, Nanometer Silicon Dots." In 1998 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 1998. http://dx.doi.org/10.7567/ssdm.1998.c-1-7.

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Saib, Waheeda, Petros Wallden, and Ismail Akhalwaya. "The Effect of Noise on the Performance of Variational Algorithms for Quantum Chemistry." In 2021 IEEE International Conference on Quantum Computing and Engineering (QCE). IEEE, 2021. http://dx.doi.org/10.1109/qce52317.2021.00020.

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Barbagiovanni, Eric G., David J. Lockwood, Raimundo N. Costa Filho, Lyudmila V. Goncharova, and Peter J. Simpson. "Quantum confinement in Si and Ge nanostructures: effect of crystallinity." In Photonics North 2013, edited by Pavel Cheben, Jens Schmid, Caroline Boudoux, Lawrence R. Chen, André Delâge, Siegfried Janz, Raman Kashyap, David J. Lockwood, Hans-Peter Loock, and Zetian Mi. SPIE, 2013. http://dx.doi.org/10.1117/12.2036323.

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Arora, Manju, Santosh Singh, and Sukhvir Singh. "Quantum confinement effect on photoluminescence of nanocrystalline ZnO thin films." In 16th International Workshop on Physics of Semiconductor Devices, edited by Monica Katiyar, B. Mazhari, and Y. N. Mohapatra. SPIE, 2012. http://dx.doi.org/10.1117/12.927415.

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Watanabe, Hiroshi, Ken Uchida, and Atsuhiro Kinoshita. "Quantum Confinement Effect of Ultrathin-SOI on double-gate-nMOSFETs." In 2003 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2003. http://dx.doi.org/10.7567/ssdm.2003.d-3-4.

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