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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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TL;DR: In this study, a self-consistent theoretical model is proposed to study the piezo-phototronic effect in the framework of perturbation theory in quantum mechanics and its validity and universality are well-proven.
Abstract: With enhancements in the performance of optoelectronic devices, the field of piezo-phototronics has attracted much attention, and several theoretical works have been reported based on semiclassical models. At present, the feature size of optoelectronic devices are rapidly shrinking toward several tens of nanometers, which results in the quantum confinement effect. Starting from the basic piezoelectricity equation, Schrodinger equation, Poisson equation, and Fermi’s golden rule, a self-consistent theoretical model is proposed to study the piezo-phototronic effect in the framework of perturbation theory in quantum mechanics. The validity and universality of this model are well-proven with photoluminescence measurements in a single GaN/InGaN quantum well and multiple GaN/InGaN quantum wells. This study provides important insight into the working principle of nanoscale piezo-phototronic devices as well as guidance for the future device design.
59 citations
TL;DR: The findings reported herein suggest that the atomic inorganic ligand reinforces the influence of quantum confinement on the solar energy conversion efficiency of QDSSCs.
Abstract: Light absorption and electron injection are important criteria determining solar energy conversion efficiency. In this research, monodisperse CdSe quantum dots (QDs) are synthesized with five different diameters, and the size-dependent solar energy conversion efficiency of CdSe quantum dot sensitized solar cell (QDSSCs) is investigated by employing the atomic inorganic ligand, S2–. Absorbance measurements and transmission electron microscopy show that the diameters of the uniform CdSe QDs are 2.5, 3.2, 4.2, 6.4, and 7.8 nm. Larger CdSe QDs generate a larger amount of charge under the irradiation of long wavelength photons, as verified by the absorbance results and the measurements of the external quantum efficiencies. However, the smaller QDs exhibit faster electron injection kinetics from CdSe QDs to TiO2 because of the high energy level of CBCdSe, as verified by time-resolved photoluminescence and internal quantum efficiency results. Importantly, the S2– ligand significantly enhances the electronic coup...
58 citations
Patent•
22 Aug 1995TL;DR: In this article, a quantum well semiconductor light emitting devices such as lasers that utilize resonant tunneling for carrier injection and spatially-diagonal transitions between an energy state in the conduction band of one quantum well and an energy states in the valence band of the adjacent quantum well for light emission, resulting in much improvement in both radiative efficiency and carrier injection efficiency.
Abstract: The present invention relates to quantum well semiconductor light emitting devices such as lasers that utilize resonant tunneling for carrier injection and spatially-diagonal transitions between an energy state in the conduction band of one quantum well and an energy state in the valence band of the adjacent quantum well for light emission, resulting in much improvement in both radiative efficiency and carrier injection efficiency. An elementary structure of the invented devices comprises two spatially coupled quantum wells residing in conduction and valence bands respectively wherein the valence band-edge in one quantum well is higher than the conduction band-edge of the other quantum well. Each quantum well contains at least one energy state formed by the quantum size effect. Light emission occurs by the transition of electrons from the state which is higher in energy in the conduction band quantum well to the state in the valence band quantum well, and the emission wavelength is inversely proportional to the energy difference between the two states which can be easily tailored by adjusting quantum well thicknesses. Cascade emission is realized in a superlattice structure which is constructed by periodically stacking many repeated elementary device structures.
57 citations
TL;DR: In this article, the authors analyzed the nonlinear optical properties of semiconductor box so small that quantum confinement effect works in all three dimensions, and showed that the third order optical polarizability of an assembly of such quantum boxes is enhanced by a number of unit cells in the box through the effect of the giant oscillator strength when the box size satisfies the conditions given in terms of sizequantization energy, exciton binding energy, interaction energy of two excitations and the off-resonance energy.
56 citations
TL;DR: Graphene/Si quantum dot (QD) heterojunction diodes are reported for the first time and the photoresponse is remarkably enhanced in the near-ultraviolet range compared to commercially available bulk-Si photodetectors.
Abstract: Graphene/Si quantum dot (QD) heterojunction diodes are reported for the first time The photoresponse, very sensitive to variations in the size of the QDs as well as in the doping concentration of graphene and consistent with the quantum-confinement effect, is remarkably enhanced in the near-ultraviolet range compared to commercially available bulk-Si photodetectors The photoresponse proves to be dominated by the carriertunneling mechanism
56 citations