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Potential well
About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.
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Patent•
22 May 1991
TL;DR: In this paper, a quantum well structure is disclosed, which is comprised of a well layer of a thickness substantially equal to the de Broglie wavelength of electrons and carrier confinement layers of an energy gap greater than that of the quantum well layer.
Abstract: A quantum well structure is disclosed, which is comprised of a quantum well layer of a thickness substantially equal to the de Broglie wavelength of electrons and carrier confinement layers of an energy gap greater than that of the quantum well layer. A second material of a lattice constant different from that of a first material primarily for the quantum well layer is disposed in the quantum well layer to provide a phase shift in the period of the crystal lattice of the first material, thereby forming energy levels in the forbidden band of the quantum well layer. A semiconductor device which employs such a quantum well structure and is so constructed as to utilize its physical phenomenon which is caused by the energy levels in the forbidden band. In concrete terms, the present invention has its feature in allowing ease in the fabrication of an intermediate infrared or blue light emitting device, for instance.
17 citations
TL;DR: In this article, a large nonresonant optical Kerr coefficient without apparent nonlinear absorption was obtained from ZnSe-doped glass thin films grown by pulsed laser deposition.
Abstract: Large nonresonant optical Kerr coefficient without apparent nonlinear absorption was obtained from ZnSe-doped glass thin films grown by pulsed laser deposition. A third nonlinear refractive index of +0.87 to 1.56 cm2/GW and fifth order of +17.2 cm4/GW2 were measured for a light beam having femtosecond pulsewidth with photon energy below one half bandgap using the Z-scan method. Besides the enhancement of the nonlinear refractive index results from the two-photon near resonance and quantum confinement effect, the intensity-induced saturation of nonlinear refractive index is explained by the quadratic optical Stark shift.
17 citations
TL;DR: In this paper, a lattice-matched multiple quantum well (MQW) structures have been grown by metalorganic vapor phase epitaxy (MOVPE) and low-temperature photoluminescence (PL) measurements for the varied well widths (L z = 36, 24, and 16 A) have revealed that the quantum confinement effect to the well manifests itself only in narrow wells whose width is comparable with or shorter than the spatial extent of localized excitons.
17 citations
TL;DR: In this article, a well-crystallized and size-tuned ZnO quantum dots (QDs) were prepared by pulsed laser ablation and following size classification using a differential mobility analyzer.
Abstract: Well-crystallized and size-tuned ZnO quantum dots (QDs) were prepared by pulsed laser ablation and following size classification using a differential mobility analyzer. Photoluminescence (PL) spectra of the ZnO QDs showed predominant ultraviolet (UV) emission. The finely size-tuned ZnO QDs allowed us to precisely evaluate the quantum confinement effect, i.e., the size-driven color-tunable behavior in the UV emission range. The faint green luminescence found in the PL spectra and the low Stokes shifts of several tens meV demonstrated that the present QDs are almost free from defects. These features are quite favorable for use in future optoelectronic devices.
17 citations
TL;DR: In this article, the band-gap energy of most of the Si nanoparticles is estimated to be 2.5-3.3 eV from the PL spectra, corresponding to the Si particle size of 1.9−3.2 nm.
Abstract: Si nanoparticles are produced from Si swarf which is a waste during slicing Si ingots to produce Si wafers for solar cell use. The beads mill method produces flake-like Si with scores of nanometers width from Si swarf. Subsequent photochemical dissolution with light longer than 560 nm wavelength in a 0.5 % HF solution results in sphere-shaped Si nanoparticles of 1–7 nm diameter. Si nanoparticles dispersed in ethanol show blue photoluminescence at ~400 nm (3.1 eV) under UV irradiation, indicating band-gap widening due to the quantum confinement effect. The band-gap energy of most of the Si nanoparticles is estimated to be 2.5–3.3 eV from the PL spectra, corresponding to the Si nanoparticle size of 1.9–3.2 nm. On the other hand, Si nanoparticles produced by immersion in the HF solution in the dark show much weaker blue photoluminescence. These results demonstrate that the Si dissolution reaction is greatly enhanced by photo-generated holes.
17 citations