Piezoelectric InAs (211)B quantum dots grown by molecular beam epitaxy: Structural and optical properties

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3510490· OSTI ID:21537934

Dialynas, G E ^[1]; Kalliakos, S; Xenogianni, C ^[2]; Androulidaki, M ^[3]; Kehagias, T; Komninou, P ^[4]; Savvidis, P G; Pelekanos, N T ^[2]; Hatzopoulos, Z ^[1]

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1. Department of Physics, University of Crete, P.O. Box 2208, 71003 Heraklion (Greece)
2. Department of Materials Science and Technology, University of Crete, P.O. Box 2208, 71003 Heraklion (Greece)
3. Microelectronics Research Group, IESL-FORTH, P.O. Box 1385, 71110 Heraklion (Greece)
4. Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

The structural and optical properties of piezoelectric (211)B InAs nanostructures grown by molecular beam epitaxy are systematically investigated as a function of the various growth parameters. Depending on the specific growth conditions, we show that the InAs nanostructures take the form of a quantum dot (QD) or a quantum dash, their height ranges between 2 and 20 nm, and their density varies from a few times 10{sup 8} cm{sup -2} all the way up to a few times 10{sup 10} cm{sup -2}. The (211)B QDs are characterized by large aspect ratios, which are compatible with a truncated pyramid morphology. By analyzing the QD emission spectrum, we conclude that only small size QDs, with heights less than 3 nm, are optically active. This is consistent with high resolution transmission electron microscopy observations showing that large QDs contain misfit dislocations, whereas small QDs are dislocation-free. The formation of a two-dimensional wetting layer is observed optically, and its thickness is determined to be between 0.30 and 0.39 nm. Finally, the large blueshift in the QD emission observed with increasing excitation power represents a clear evidence of the strong built-in piezoelectric field present in these dots.

• OSTI ID: 21537934
• Journal Information: Journal of Applied Physics, Vol. 108, Issue 10; Other Information: DOI: 10.1063/1.3510490; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ASPECT RATIO
CRYSTAL STRUCTURE
DISLOCATIONS
EMISSION
EMISSION SPECTRA
EXCITATION
INDIUM ARSENIDES
LAYERS
MOLECULAR BEAM EPITAXY
NANOSTRUCTURES
OPTICAL PROPERTIES
PIEZOELECTRICITY
QUANTUM DOTS
RESOLUTION
SEMICONDUCTOR MATERIALS
SPECTRAL SHIFT
TRANSMISSION ELECTRON MICROSCOPY
ARSENIC COMPOUNDS
ARSENIDES
CRYSTAL DEFECTS
CRYSTAL GROWTH METHODS
DIMENSIONLESS NUMBERS
ELECTRICITY
ELECTRON MICROSCOPY
ENERGY-LEVEL TRANSITIONS
EPITAXY
INDIUM COMPOUNDS
LINE DEFECTS
MATERIALS
MICROSCOPY
PHYSICAL PROPERTIES
PNICTIDES
SPECTRA