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Open Access Nano Express

Anisotropic Confinement, Electronic Coupling and Strain Induced Effects Detected by Valence-Band Anisotropy in Self-Assembled Quantum Dots

L Villegas-Lelovsky12*, MD Teodoro13, V Lopez-Richard1, C Calseverino14, A Malachias4, E Marega35, BL Liang37, Yu I Mazur3, GE Marques1, C Trallero-Giner6 and GJ Salamo3

Author affiliations

1 Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP 13565-905, Brazil

2 Instituto de Física, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais 38400-902, Brazil

3 Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, AR 72701, USA

4 Laboratório Nacional de Luz Síncrotron, Campinas, Brazil

5 Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP 13560-970, Brazil

6 Faculty of Physics, Havana University, 10400, Havana, Cuba

7 Department of Electrical Engineer, University of California, Los Angeles, CA 90095, USA

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Citation and License

Nanoscale Res Lett 2011, 6:56  doi:10.1007/s11671-010-9786-8

Published: 1 October 2010

Abstract

A method to determine the effects of the geometry and lateral ordering on the electronic properties of an array of one-dimensional self-assembled quantum dots is discussed. A model that takes into account the valence-band anisotropic effective masses and strain effects must be used to describe the behavior of the photoluminescence emission, proposed as a clean tool for the characterization of dot anisotropy and/or inter-dot coupling. Under special growth conditions, such as substrate temperature and Arsenic background, 1D chains of In0.4Ga0.6 As quantum dots were grown by molecular beam epitaxy. Grazing-incidence X-ray diffraction measurements directly evidence the strong strain anisotropy due to the formation of quantum dot chains, probed by polarization-resolved low-temperature photoluminescence. The results are in fair good agreement with the proposed model.

Keywords:
Molecular beam epitaxy; Self-assembled quantum dots; Inter-dot coupling; Anisotropic effects; Linear polarized photoluminescence emission; Grazing-incidence X-ray diffraction synchrotron; Optoelectronic