Enhancement of Optical Anisotropy by Interconnection Effect along Growth Direction in Multistacked Quantum Dots

ABSTRACTThe growth mode of CdSe layers grown by migration enhanced epitaxy between ZnSe barriers has been investigated. In situ reflection high-energy electron diffraction shows a gradual transition to a three-dimensional growth mode which, however, is not accompanied by a change of the surface lattice constant. High-resolution transmission electron micrographs reveal a strong Cd diffusion, leading to ternary ZnCdSe quantum wells. Furthermore. composition fluctuations perpendicular to the growth direction on a nanometer scale are found already prior to the beginning of the growth mode transition. In the case of heterostructures containing a CdSe layer that has undergone the growth mode transition, micrographs show Cd-rich quantum dots with diameters of around 8 nm and heights of around 1.5 nm within a ternary quantum well. By spatially resolved photoluminescence the emission from single quantum dots could be observed. The polarization dependence of the emission from single dots indicates an asymmetric shape of the dots with certain preferential orientations along the [110] and [110] directions.

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Effect of magnetic field on optical anisotropy of CdZnSe quantum dots

Journal of Physics Conference Series ◽

10.1088/1742-6596/245/1/012036 ◽

2010 ◽

Vol 245 ◽

pp. 012036

Author(s):

Jitendra Kumar ◽

Sheetal Kapoor

Keyword(s):

Magnetic Field ◽

Quantum Dots ◽

Optical Anisotropy

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Microstructures and Growth Characteristics of Self-Assembled InAs/GaAs Quantum Dots Investigated by Transmission Electron Microscopy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.26-28.1207 ◽

2007 ◽

Vol 26-28 ◽

pp. 1207-1210

Author(s):

Hyung Seok Kim ◽

Ju Hyung Suh ◽

Chan Gyung Park ◽

Sang Jun Lee ◽

Sam Kyu Noh ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Quantum Dots ◽

Chemical Potential ◽

Early Stage ◽

Compressive Strain ◽

Potential Gradient ◽

Growth Direction ◽

Transmission Electron ◽

Self Assembled

The microstructure and strain characteristics of self-assembled InAs/GaAs quantum dots (QDs) were studied by using transmission electron microscopy. Compressive strain was induced to uncapped QDs from GaAs substrate and the misfit strain largely increased after the deposition of GaAs cap layer. Tensile strain outside QD was extended along the vertical growth direction; up to 15 nm above the wetting layer. Vertically nonaligned and aligned stacked QDs were grown by adjusting the thickness of GaAs spacer layers. The QDs with a lens-shaped morphology were formed in the early stage of growth, and their apex was flattened by the out-diffusion of In atoms upon GaAs capping. However, aligned QDs maintained their lens-shaped structure with round apex after capping. It is believed that their apex did not flatten because the chemical potential gradient of In was relatively low due to the adjacent InAs QD layers.

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Optical anisotropy of excitons and biexcitons in InP quantum dots

Journal of Luminescence ◽

10.1016/j.jlumin.2006.01.178 ◽

2007 ◽

Vol 122-123 ◽

pp. 424-426 ◽

Cited By ~ 1

Author(s):

Yasuaki Masumoto ◽

Kiyoshi Mizuochi ◽

Kazuki Bando ◽

Yoko Karasuyama

Keyword(s):

Quantum Dots ◽

Optical Anisotropy ◽

Inp Quantum Dots

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Determination of the Strain Status of GaAs/AlAs Quantum Wires and Quantum Dots

MRS Proceedings ◽

10.1557/proc-358-975 ◽

1994 ◽

Vol 358 ◽

Author(s):

A.A. Darhuber ◽

G. Bauer ◽

P.D. Wang ◽

Y.P. Song ◽

C.M. Sotomayor Torres ◽

...

Keyword(s):

Quantum Dots ◽

Electron Beam Lithography ◽

Quantum Wires ◽

Growth Direction ◽

Reciprocal Space ◽

Reciprocal Space Mapping ◽

X Ray ◽

Periodic Arrays ◽

Strain Status

ABSTRACTWe have investigated periodic arrays of 150 and 175 nm wide GaAs-AlAs quantum wires and quantum dots, fabricated by electron beam lithography and SiCI4/O2 reactive ion etching, by means of reciprocal space mapping using triple axis x-ray diffractometry (TAD). The reciprocal space maps reveal that after the fabrication process the lattice constant along the growth direction slightly increases for the wires and even more so for the dots.

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