Quantum Wires
Mostrando 1-12 de 24 artigos, teses e dissertações.
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1. Estudo de pontos quânticos auto-organizados de InAs por fotoluminescência
Semiconductor structures with high confinement degree, such as quantum wells, quantum wires and quantum dots, have been of great interest, both from the technological point of view and for basic research. Self-Assembled Quantum Dots (SAQD`s) appear spontaneously, as a consequence of the lattice mismatch of the material deposited in relation to the substrate,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/02/2010
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2. Estudo das propriedades termoelétricas de fios quânticos de telureto de chumbo / Study of thermoelectrical properties in lead telluride quantum wires
This work presents a theoretical study of the electronic and thermoelectric properties of PbTe quantum wires. Thermoelectric effects in nanostructured materials of IV-VI family, in particular superlattices, quantum well and quantum wire, have been studied a lot, because they present an enhancement in figure of merit relatively to bulk. Researching theoretica
Publicado em: 2010
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3. Estudo das propriedades termoelétricas de fios quânticos de telureto de chumbo / Study of thermoelectrical properties in lead telluride quantum wires
Neste trabalho é apresentado um estudo teórico das propriedades eletrônicas e termoelétricas de fios quânticos de PbTe. Efeitos termoelétricos em materiais nanoestruturados da família IV-VI, em particular super-redes, poços e fios quânticos, têm sido muito estudados por apresentarem um aumento no valor da figura de mérito em relação ao bulk (mat
Publicado em: 2010
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4. Prorpiedades de transportes em fios e poÃos quÃnticos. / Transport Properties of Quantum Wells and Quantum Wires
Materiais semicondutores sÃo os principais responsÃveis pelo grande crescimento da indÃstria eletrÃnica e pelo surgimento de novas tecnologias. A criaÃÃo de heteroestruturas possibilitou um grande impulso à fÃsica do estado sÃlido. Atualmente, o estudo de semicondutores està concentrado em sistemas de dimensionalidade reduzida, como os poÃos, fios
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/07/2009
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5. Propriedades ópticas anômalas de poços e fios quânticos de InGaAs/InP vicinais
The dynamic and the lateral transport of carriers in quantum wells and quantum wires of InGaAs grown on vicinal InP substrates were investigated by spectrally and spatially resolved photoluminescence techniques. Simulation of the results of spectrally integrated photoluminescence using rate equations showed that the carrier capture and lifetime of the confin
Publicado em: 2007
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6. Hydrogenic impurity in ridge quantum wire
The binding energies as well as wave functions of hydrogenic impurities located in V-groove GaAs/Al xGa1-xAs quantum wires are calculated for different positions of the impurity inside the wires. The variational method is used and the carrier ground states are analytically calculated by an effective potential scheme together with a suitable coordinate transf
Brazilian Journal of Physics. Publicado em: 2006-12
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7. Effects of effective mass discontinuity on the conductance of three-dimensional quantum wires
We calculate the conductance of three-dimensional semiconductor quantum wires considering different effective masses in the contacts and in the channel. We show that, with respect to the case with equal masses in the channel and in the contacts, the amplitude of the conductance oscillations increases if the electron effective mass in the channel is larger an
Brazilian Journal of Physics. Publicado em: 2006-09
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8. Hydrostatic pressure and electric-field effects on the shallow donor impurity states in GaAs-Ga0.7Al0.3As quantum-well wires
Using a variational procedure within the effective-mass approximation, we have made a theoretical study of the effects of hydrostatic pressure and applied electric fields on the binding energy of a shallow-donor impurity in square-transversal section GaAs-Ga0.7Al0.3As quantum-well wires. The electric field is applied in a plane of the transversal section of
Brazilian Journal of Physics. Publicado em: 2006-09
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9. Square-gradient scattering mechanism in surface-corrugated waveguides
In this work we study the surface scattering mechanisms from rough surfaces of a multimode quasi-1D waveguide (conducting quantum wires). The square-gradient scattering mechanism, which was missed in existing studies of the transport through surface-corrugated waveguides, is discovered. The main attention is paid to the interplay between the new mechanism an
Brazilian Journal of Physics. Publicado em: 2006-09
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10. Intersubband excitations at finite temperatures and their roles in different quasi-one-dimensional systems
We theoretically study many-body excitations in three different quasi-one-dimensional (Q1D) electron systems: (i) those formed on the surface of liquid Helium; (ii) in two coupled semiconductor quantum wires; and (iii) Q1D electrons embedded in polar semiconductor-based quantum wires. Our results show intersubband coupling between higher subbands and the two
Brazilian Journal of Physics. Publicado em: 2006-06
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11. Hydrogenated Ge nanocrystals: band gap evolution with increasing size
The electronic band structure of various Ge quantum wires of different sizes, with hydrogenated surfaces, is studied using a nearest-neighbor empirical tight-binding Hamiltonian by means of a sp³s* atomic orbitals basis set. We suppose that the nanostructures have the same lattice structure and the same interatomic distance as in bulk Ge and that all the da
Brazilian Journal of Physics. Publicado em: 2006-06
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12. Binding energy and photoionization cross-section in GaAs quantum well-wires and quantum dots: magnetic field and hydrostatic pressure effects
Using a variational procedure for a hydrogenic donor-impurity we have investigated the influence of an axial magnetic field and hydrostatic pressure in the binding energy and the impurity-related photoionization cross-section in 1D and 0D GaAs low dimensional systems. Our results are given as a function of the radius, the impurity position, the polarization
Brazilian Journal of Physics. Publicado em: 2006-06