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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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Journal ArticleDOI
Dongsheng Xu1, Guolin Guo1, Linlin Gui1, Youqi Tang1, G. G. Qin1 
TL;DR: In this paper, the authors studied the evolution of the optical absorption of free-standing PS films during thermal oxidation at 200°C in air and showed that the optical gap associated with each crystallite should increase during the thermal oxidation process, due to the quantum confinement effect.
Abstract: We have systematically studied the evolution of the optical absorption of free- standing PS films during thermal oxidation at 200°C in air. Our experiment results show the evolution of transmission curve is quite complicated, which red-shifts first and then blue- shifts during thermal oxidation. At the same time, the transmission at the low energy decreases first and then increases. We propose an explanation as follows: (1) the energy gap associated with each crystallite should increase during thermal oxidation process, due to the quantum confinement effect; (2) the energy gap should decrease with an increase in oxygen termination atoms. Both the increasing of the gap due to the quantum confinement effect and the decreasing of the gap due to the Si-O bond formation cause a complicated evolution of optical absorption.

5 citations

Proceedings ArticleDOI
11 Jul 2005
TL;DR: Using low-temperature near-field spectroscopy of isolated ZnO nanorod single-quantum well structures (SQWs), the dependence of the quantum confinement effect of the photoluminescence peak on the well width was observed as mentioned in this paper.
Abstract: Using low-temperature near-field spectroscopy of isolated ZnO nanorod single-quantum-well structures (SQWs), the dependence of the quantum confinement effect of the photoluminescence peak on the well width was observed. Furthermore, the homogeneous linewidth of the isolated ZnO SQWs was determined as small as 3 meV.

5 citations

Journal ArticleDOI
TL;DR: The results demonstrate a potential method to measure the dynamic behavior of a single molecule confined in a tunneling junction, where the molecule-substrate interaction can be purposely tuned.
Abstract: Two low-energy excitations of a single water molecule are observed via inelastic electron tunneling spectroscopy, where a significant enhancement is achieved by attaching the molecule to the tip apex in a scanning tunneling microscope. Density functional theory simulations and quantum mechanical calculations of an asymmetric top are carried out to reveal the origin of both excitations. Variations in tunneling junction separation give rise to the quantum confinement effect on the quantum state of a water molecule in the tunneling junction. Our results demonstrate a potential method for measuring the dynamic behavior of a single molecule confined in a tunneling junction, where the molecule–substrate interaction can be purposely tuned.

5 citations

Journal ArticleDOI
TL;DR: In this paper, a high-density In0.2Ga0.8As/Al 0.38Ga 0.62As QWR structure was successfully grown on submicron gratings by a constant metalorganic chemical vapor deposition (MOCVD) growth technique.
Abstract: High-density In0.2Ga0.8As/Al0.2Ga0.8As quantum wire (QWR) gain-coupled distributed feedback (DFB) laser structures and an In0.2Ga0.8As/Al0.38Ga0.62As QWR structure were successfully grown on submicron gratings by a constant metalorganic chemical vapor deposition (MOCVD) growth technique in which submicron gratings were preserved even after an epitaxial growth of 1 µm thickness. Owing to the stronger quantum confinement effect of the AlGaAs barrier layer, strong photoluminescence from the QWR was observed even at room temperature. The Stokes shift of the QWR in the DFB laser structure was about 6 meV which indicates the high optical quality of the InGaAs/AlGaAs QWRs. The photoluminescence excitation spectra of the strained QWR did not show marked polarization anisotropy in contrast to those of the lattice-matched GaAs QWR due to the strain effects. It is expected that the high-density QWR structure fabricated using the constant MOCVD growth technique will be widely used in future photonic devices such as laser diodes and optical modulators.

5 citations

Proceedings ArticleDOI
TL;DR: In this paper, a continuous blue shift of the photoluminescence (PL) peak from 660nm to 440nm was observed by increasing the NH 3 flow rate from 20 to 150sccm, while the flow rate of N 2 diluted 2% SiH 4 was fixed at 650 sccm. This controllable PL was attributed to the quantum confinement effect of Si quantum dots (QDs) which were formed during the deposition process and embedded in the SiN x films.
Abstract: Intense visible blue to red emissions were obtained from SiN x thin films prepared by plasma enhanced chemical vapor deposition (PECVD) using SiH 4 and NH 3 as the source gases. A continuous blue shift of the photoluminescence (PL) peak from 660nm to 440nm was observed by increasing the NH 3 flow rate from 20 to 150sccm, while the flow rate of N 2 diluted 2% SiH 4 was fixed at 650sccm. This controllable PL was attributed to the quantum confinement effect of Si quantum dots (QDs) which were formed during the deposition process and embedded in the SiN x films. White photoluminescence with multiple emission peaks was achieved for potential solid state lighting applications from multi-layered SiN x films by changing the SiH 4 /NH 3 ratio during the deposition process. This was attributed to a combination of Si quantum dots with different sizes within the different layers. Surface texturing of the thin film samples was conducted by potassium hydroxide (0.56%) etching the (100) Si substrate for 3~40 min at 80°C before deposition. The reflectivity of the etched samples decreased with increasing etch time due to increased surface roughness. The extraction efficiency of light emission from the textured SiN x thin films was significantly improved, owing to a depression of the internal reflection and interference effects. In addition, the elimination of the multiple emission peaks by surface texturing significantly affected the color coordinates of the output spectrum.

5 citations


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