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Quantum wire

About: Quantum wire is a research topic. Over the lifetime, 5580 publications have been published within this topic receiving 105513 citations.


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Journal ArticleDOI
TL;DR: In this paper, free standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithography using electrochemical and chemical dissolution steps to define networks of isolated wires out of bulk wafers.
Abstract: Indirect evidence is presented that free‐standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithography. The novel approach uses electrochemical and chemical dissolution steps to define networks of isolated wires out of bulk wafers. Mesoporous Si layers of high porosity exhibit visible (red) photoluminescence at room temperature, observable with the naked eye under <1 mW unfocused (<0.1 W cm−2) green or blue laser line excitation. This is attributed to dramatic two‐dimensional quantum size effects which can produce emission far above the band gap of bulk crystalline Si.

7,393 citations

Journal ArticleDOI
02 Nov 2007-Science
TL;DR: The quantum phase transition at the critical thickness, d = 6.3 nanometers, was independently determined from the magnetic field–induced insulator-to-metal transition, providing experimental evidence of the quantum spin Hall effect.
Abstract: Recent theory predicted that the quantum spin Hall effect, a fundamentally new quantum state of matter that exists at zero external magnetic field, may be realized in HgTe/(Hg,Cd)Te quantum wells. We fabricated such sample structures with low density and high mobility in which we could tune, through an external gate voltage, the carrier conduction from n-type to p-type, passing through an insulating regime. For thin quantum wells with well width d 6.3 nanometers), the nominally insulating regime showed a plateau of residual conductance close to 2e(2)/h, where e is the electron charge and h is Planck's constant. The residual conductance was independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance was destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, d = 6.3 nanometers, was also independently determined from the magnetic field-induced insulator-to-metal transition. These observations provide experimental evidence of the quantum spin Hall effect.

4,343 citations

Journal ArticleDOI
03 Apr 1997-Nature
TL;DR: In this article, electrical transport measurements on individual single-wall nanotubes have been performed to confirm the theoretical predictions of single-walled nanotube quantum wires, and they have been shown to act as genuine quantum wires.
Abstract: Carbon nanotubes have been regarded since their discovery1 as potential molecular quantum wires. In the case of multi-wall nanotubes, where many tubes are arranged in a coaxial fashion, the electrical properties of individual tubes have been shown to vary strongly from tube to tube2,3, and to be characterized by disorder and localization4. Single-wall nanotubes5,6 (SWNTs) have recently been obtained with high yields and structural uniformity7. Particular varieties of these highly symmetric structures have been predicted to be metallic, with electrical conduction occurring through only two electronic modes8–10. Because of the structural symmetry and stiffness of SWNTs, their molecular wavefunctions may extend over the entire tube. Here we report electrical transport measurements on individual single-wall nanotubes that confirm these theoretical predictions. We find that SWNTs indeed act as genuine quantum wires. Electrical conduction seems to occur through well separated, discrete electron states that are quantum-mechanically coherent over long distance, that is at least from contact to contact (140nm). Data in a magnetic field indicate shifting of these states due to the Zeeman effect.

2,678 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that a two-dimensional quantum confinement (quantum wire) in the very narrow walls between the pores not only explains the change in band gap energy but also may also explain the dissolution mechanism that leads to porous silicon formation.
Abstract: Porous silicon layers grown on nondegenerated p‐type silicon electrodes in hydrofluoric acid electrolytes are translucent for visible light, which is equivalent to an increased band gap compared to bulk silicon. It will be shown that a two‐dimensional quantum confinement (quantum wire) in the very narrow walls between the pores not only explains the change in band‐gap energy but may also be the key to better understanding the dissolution mechanism that leads to porous silicon formation.

1,705 citations

Journal Article
TL;DR: In this paper, the authors studied the effect of the density of states on phonon emission and absorption in In x Ga 1-x As/InP quantum wells and wires and showed that for a given healing power per electron, the electron temperature T e in a quantum wire can be greater or smaller than that in a corresponding quantum well, depending on the electron density n s, while the energy relaxation in quantum dots with significant quantization energies is always slower than in the corresponding well and wires.
Abstract: We report on calculations of inlrasubband and intersubband phonon scattering in quantum-confined electron gases based on lattice-matched In x Ga 1-x As/InP quantum wells. Dimensionality effects on the emission of acoustic phonons are studied comparing the scattering times of two-, one-, and zero-dimensional electron gases as a function of the lateral confinement. Optical phonon scattering in quantum wells and wires is discussed using a phenomenological broadening of the one-dimensional density of states. The energy relaxation rates of heated electron gases due to phonon emission and absorption have been calculated for lattice temperatures T 1 between 0.3 and 20 K. For a given healing power per electron, the electron temperature T e in a quantum wire can be greater or smaller than that in the corresponding quantum well, depending on the electron density n s , while the energy relaxation in quantum dots with significant quantization energies is always slower than in the corresponding wells and wires.

785 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202314
202222
202135
202053
201961
201872