Topic
Quantum well
About: Quantum well is a research topic. Over the lifetime, 44627 publications have been published within this topic receiving 674023 citations. The topic is also known as: QW & quantum potential well.
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TL;DR: In this article, a review of InAs/AlSb quantum wells is presented, which is an ideal medium to study the low-temperature transport properties in InAs itself, with gate-induced electron sheet concentrations on the order 10 12 cm −2, they exhibit a pronounced conductivity quantization.
Abstract: The three semiconductors InAs, GaSb, and AlSb form an approximately lattice-matched set around 6.1 A , covering a wide range of energy gaps and other properties. Of particular interest are heterostructures combining InAs with one or both of the antimonides, and they are emphasized in this review. In addition to their use in conventional device types (FETs, RTDs, etc.), several heterostructure configurations with unique properties have been explored, especially InAs/AlSb quantum wells and InAs/GaSb superlattices. InAs/AlSb quantum wells are an ideal medium to study the low-temperature transport properties in InAs itself. With gate-induced electron sheet concentrations on the order 10 12 cm −2 , they exhibit a pronounced conductivity quantization. The very deep wells (1.35 eV ) provide excellent electron confinement, and also permit modulation doping up to at least 10 13 electrons cm −2 . Because of the very low effective mass in InAs, heavily doped wells are essentially metals, with Fermi energies around 200 meV , and Fermi velocities exceeding 10 8 cm s −1 . Contacted with superconducting electrodes, such structures can act as superconductive weak links. InAs/GaSb-related superlattices with their broken-gap lineup behave like semimetals at large lattice periods, but if the lattice period is shortened, increasing quantization effects cause a transition to a narrow-gap semiconductor, making such structures of interest for infrared detectors, often combined with the deliberate addition of strain.
302 citations
TL;DR: In this article, a GaAs/AlxGa(1−x)As quantum well laser has been demonstrated via organometallic chemical vapor deposition on relaxed graded Ge/GeSi/Si virtual substrates on Si.
Abstract: GaAs/AlxGa(1−x)As quantum well lasers have been demonstrated via organometallic chemical vapor deposition on relaxed graded Ge/GexSi(1−x) virtual substrates on Si. A number of GaAs/Ge/Si integration issues including Ge autodoping behavior in GaAs, reduced critical thickness due to thermal expansion mismatch, and complications with mirror facet cleaving have been overcome. Despite unoptimized laser structures with high series resistance and large threshold current densities, surface threading dislocation densities for GaAs/AlGaAs lasers on Si substrates as low as 2×106 cm−2 permitted continuous room-temperature lasing at a wavelength of 858 nm. The laser structures are uncoated edge-emitting broad-area devices with differential quantum efficiencies of 0.24 and threshold current densities of 577 A/cm2. Identical devices grown on commercial GaAs substrates showed similar behavior. This comparative data agrees with previous measurements of near-bulk minority carrier lifetimes in GaAs grown on Ge/GeSi/Si substrates.
301 citations
TL;DR: Quantum well structured CdSe nanoribbons with uniform and ultrathin thickness of 1.4 nm were synthesized from the low-temperature reaction of CdCl2 and ammonium selenocarbamate and exhibited an extremely narrow photoluminescence band.
Abstract: Quantum well structured CdSe nanoribbons with uniform and ultrathin thickness of 1.4 nm were synthesized from the low-temperature reaction of CdCl2 and ammonium selenocarbamate. The CdSe nanoribbons exhibited an extremely narrow photoluminescence band with fwhm of 70 meV.
301 citations
TL;DR: In this paper, a study using superconducting leads in contact with a quantum well reveals the presence of supercurrents along one-dimensional sample edges of a quantum spin Hall state.
Abstract: Majorana fermions, which are their own antiparticles, are expected to exist in topological superconductors. A study using superconducting leads in contact with a quantum well reveals the presence of supercurrents along one-dimensional sample edges of a quantum spin Hall state. These edge supercurrents are topological.
300 citations
TL;DR: It is found that the strong electronic confinement in these quantum dots reflects itself in the ground-state energy and in the impurity binding energies, which are higher than those found in GaAs-(Ga,Al)As quantum wells and quantum-well wires.
Abstract: The ground-state energy and the binding energy of shallow hydrogenic impurities in spherical GaAs-(Ga,Al)As quantum dots have been calculated as functions of the radius of the dot. The binding energy has been calculated following a variational procedure within the effective-mass approximation. We have used a finite confining potential well with depth determined by the discontinuity of the band gap in the quantum dot and the cladding. Calculations were also performed for an infinite confining potential. For the infinite potential well we found that the impurity binding energy increases as the dot radius decreases whereas in the finite potential-well situation, the binding energy reaches a peak value as the dot radius decreases and then diminishes to a limiting value corresponding to the radius for which there are no bound states in the well. We found that the strong electronic confinement in these quantum dots reflects itself in the ground-state energy and in the impurity binding energies, which are higher than those found in GaAs-(Ga,Al)As quantum wells and quantum-well wires.
300 citations