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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 article, the quantum confinement effect and stability of 3C-SiC nanocrystals in aqueous solution as well as photoluminescence properties in water suspensions with different pH values are reviewed based on design and analysis of surface structures.
Abstract: The influence of water permeates almost all areas including biochemistry, chemistry, physics and is particularly evident in phenomena occurring at the interfaces of solid surface such as SiC nanocrystals, which are promising nanomaterials and exhibit unique surface chemical properties. In this paper, the quantum confinement effect and stability of 3C-SiC nanocrystals in aqueous solution as well as photoluminescence properties in water suspensions with different pH values are reviewed based on design and analysis of surface structures. On this basis, the significant progress of 3C-SiC nanocrystals in efficiently splitting water into usable hydrogen is summarized and the relative mechanisms are described. In addition, the water-soluble 3C-SiC quantum dots as robust and nontoxic biological probes and labels also are introduced as well as future prospects given.

12 citations

Journal ArticleDOI
TL;DR: In this paper, a photocathode with a graded Al composition structure was designed, in which the Al composition of the emission layer is decreased gradually from bulk to surface, and the outermost layer is GaAs.
Abstract: To obtain a high quantum efficiency transmission-mode GaAlAs photocathode, a photocathode with a graded Al composition structure is designed, in which the Al composition of the emission layer is decreased gradually from bulk to surface, and the outermost layer is GaAs. Based on the graded Al composition structure, GaAlAs photocathodes with different thicknesses of GaAs layers are prepared. The experimental results show that the quantum efficiency of the GaAlAs photocathode in blue-green light significantly increased when the thickness of the outermost GaAs achieves a dozen nanometers. The peak quantum efficiency of a GaAlAs photocathode with a nanoscale GaAs layer could achieve 31%, which appears at 620 nm. The nanoscale surface structure has a quantum confinement effect, which is the main factor in the increased quantum efficiency of the GaAlAs photocathode.

12 citations

Journal ArticleDOI
TL;DR: In this paper, the electronic structures of the inhomogeneous quantum dots within the framework of the effective mass theory were investigated. And the results showed that the energies of electron and hole states depend sensitively on the relative magnitude 77 of the core radius to the capped quantum dot radius.
Abstract: We investigate the electronic structures of the inhomogeneous quantum dots within the framework of the effective mass theory. The results show that the energies of electron and hole states depend sensitively on the relative magnitude 77 of the core radius to the capped quantum dot radius. The spatial distribution of the electrons and holes vary significantly when the ratio eta changes. A quantum-confinement-driven type-II-type-I transition is found in GaAs/AlxGa1-xAs-capped quantum dot structures. The phase diagram is obtained for different capped quantum dot radii. The ground-state exciton binding energy shows a highly nonlinear dependence on the innner structures of inhomogeneous quantum dots, which originates from the redistribution of the electron and hole wave functions.

12 citations

Journal ArticleDOI
Ying Zhao1, Xiuchun Yang1, Wenhai Huang1, Xiao Zou1, Zhen-guang Lu1 
TL;DR: In this paper, the formation and growth mechanism of CdS nanowires, as well as the optical properties were also analyzed in details, and the results indicated that the structure and growth process of the nanowire experience from initial nuclei, nanoparticles, linear pearl-chain structures to final nanowsires, attributed to electrostatic adsorption and ions diffusion.
Abstract: CdS nanowires were prepared by a paired cell method, using highly ordered porous anodic alumina (PAA) membranes as templates. The morphology, structure, and composition of these nanowires were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED) pattern. SEM images indicated that nanowires arrays are highly ordered and coincide with the contours of PAA. The EDS analysis, combined with HRTEM images and SEAD patterns, confirmed the formation of CdS. The formation and growth mechanism of CdS nanowires, as well as the optical properties, were also analyzed in details. The results indicated that the formation and growth of CdS nanowires experience from initial nuclei, nanoparticles, linear pearl-chain structures to final nanowires, attributed to electrostatic adsorption and ions diffusion. A strong emission with a maximum around 430 nm was observed from the synthesized CdS nanowires, which was attributed to the recombination of trapped electron/hole pairs. The absorption edge in UV–Vis spectrum of CdS/PAA nanoarrays showed a blue shift due to the quantum confinement effects. The technique can be used to fabricate other compound nanowires and newly light-emitting semiconductor materials.

12 citations

Journal ArticleDOI
TL;DR: The theoretical mechanism of luminescence in Zn Se QDs was explored and the relation of various point defect concentrations of ZnSe was analogized to compare and contrast.
Abstract: Zinc blende, sphericity, monodisperse, high luminescence ZnSe quantum dots (QDs) were synthesized by a one-step mild hydrothermal route with Zn and Se dissolved in aqueous NaOH as the source material. The structure and the morphology of the sample were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicated that the products were cubic blende ZnSe ranging from 3.2 to 4.5 nm in size. TEM images showed that the QDs have very good dispersibility and distribution. The characteristic features of the absorption and photoluminescence spectra of ZnSe quantum dots were studied at room temperature. Compared with the bulk ZnSe, the absorption edges and luminescent peaks of ZnSe QDs were blue shifted to higher energies due to the quantum confinement effect. Photoluminescence at ultraviolet excitation showed the strong emission at 390 nm related to the higher excitonic states. ZnSe QDs exhibiting photoluminescence line widths as narrow as 40-60 nm. Meanwhile, we simply explored the theoretical mechanism of luminescence in ZnSe QDs and analogized the relation of various point defect concentrations of ZnSe.

12 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
202215
202164
202062
201940
201875