Quantum Confinement Effect
Mostrando 1-12 de 14 artigos, teses e dissertações.
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1. Temperature and Deposition Time Effect on Properties and Kinetics of CdSe and CdS0.25Se0.75 Films Deposited by CBD
CdSe and CdS0.25Se0.75 thin films were grown by the Chemical Bath Deposition technique at different temperatures (50-90°C) and deposition times (5-180 min). Both kinds of films are polycrystalline, constituted by nanostructured clusters of particles. CdSe films consist in a mixture of cubic and hexagonal phases (4-8 nm crystal size), whereas only the hexago
Mat. Res.. Publicado em: 26/06/2017
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2. Structural, Optical, Morphological and Dielectric Properties of Cerium Oxide Nanoparticles
Cerium oxide (CeO2) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium o
Mat. Res.. Publicado em: 15/03/2016
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3. Efeito capacitivo em um sistema de dois pontos quânticos acoplados no regime Kondo
In this work we study a system composed by two quantum dots coupled to each other and one of each coupled to two metallic leads. Theoretically the system is described by a generalized two-impurity Anderson model. In this Hamiltonian we include both intraand inter-site electron-electron interaction, where the former is due to the confinement of electrons in a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/07/2011
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4. Tuning luminescence of 3d transition- metal doped quantum particles: Ni+2: CdS and Fe+3: CdS
The room- temperature photoluminescence of Cd1- xMxS (M=Ni, Fe) nanoparticles were investigated. Compared with the photoluminescence of CdS which peaks at 475 nm, the photoemission of CdS:Fe nanoparticles was peaking at 537 nm because of Fe acting as luminescent centers. On the other hand, the green emission (503 nm) of CdS:Ni attributed to the ¹T2g(D)→ �
Brazilian Journal of Physics. Publicado em: 2010-09
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5. O estado da arte da síntese de semicondutores nanocristalinos coloidais
Colloidal semiconductor nanocrystals, also known as quantum dots, have attracted great attention since they have interesting size-dependent properties due to the quantum confinement effect. These nanoparticles are highly luminescent and have potential applications in different technological areas, including biological labeling, light-emitting diodes and phot
Química Nova. Publicado em: 2010
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6. Estudo das propriedades estruturais e ópticas em materiais nanoestruturados a base de silício. / Study of structural and optical properties in nanostructured silicon based films.
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 ind
Publicado em: 2009
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7. Oscilador de Dirac: ImplicaÃÃes da violaÃÃo da simetria de Lorentz e da massa dependente da posiÃÃo.
In this work we study the Dirac Oscillator (DO) in a threefold way. In the first way, we study DO with Lorentz symmetry violation. This violation is implemented through vectorial and an axial terms. We realize a non-relativistic limit and we obtain that the background vector field does not modify the energy spectrum. However, in the case of the background ax
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/07/2008
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8. Decoherence and relaxation time in an ensemble of quantum dots / Tempos de relaxação e decoerencia em ensembles de pontos quanticos
Experimental measurements were carried out to determine the scales of the relaxation and decoherence time for the electronic spin as quantum bit. The structure of the exciton states was investigated with the objective to serve as intermediate states in the spin manipulation. The system studied for the implementation of the quantum computation is an ensemble
Publicado em: 2007
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9. SPIN AND CORRELATION EFFECTS IN NANOSCOPIC TRANSPORT / EFEITOS DE SPIN E CORRELAÇÃO EM TRANSPORTE NANOSCÓPICO
We investigated spin polarized transport properties through a quantum dot connected with two terminals. An electric current that circulates in our system can have its polarization modulated with an external potential that controls the spin orbit coupling (Rashba effect). We studied the effect of spin polarization n a transistor constituted by a quantum dot w
Publicado em: 2005
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10. Efeito anomalo nas medidas de lente termica em vidros com pontos quanticos de CdTe / Anomalous effect in thermal lens measurements in CdTe quantum dot doped glasses
Semiconductor doped glasses are of great interest because of their non-linear optical properties and short response time due to quantum confinement. In this work, we used the thermal lens technique to determine the thermal diffusivity (a ) and the behavior of the temperature coefficient of the refractive index (dn/dT ) in CdTe doped borosilicate glasses trea
Publicado em: 2005
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11. Electronic properties of coupled quantum rings in the presence of a magnetic field
We have studied the energy spectrum of a system formed by two concentric, coupled, semiconductor quantum rings. We have investigated the effect of a uniform magnetic field applied along the rings axis, on the energy spectrum of the system. We found that the spectrum of the coupled rings with similar confinement length corresponds roughly to the superposition
Brazilian Journal of Physics. Publicado em: 2004-06
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12. Dinamica de femtossegundos em pontos quanticos de CdTe
We study the ultrafast phenomena in CdTc Quantum Dots in Borosilicate Glasses using short laser pulses (femtoseconds) methods. Measuring the Time Resolved Differential Transmission Spectroscopy we find infrared shifts of the bleached spectra. For the interpretation of these data we study the Electronic Structure of CdTe with 0-D Quantum Confinement. We deter
Publicado em: 1998