Capping layer growth rate and the optical and structural properties of GaAsSbN-capped InAs/GaAs quantum dots

Journal Article · Tue Oct 07 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4896963· OSTI ID:22305762

Utrilla, A. D.; Guzman, A.; Hierro, A. ^[1]; Reyes, D. F.; Ben, T.; González, D. ^[2]

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1. Institute for Systems based on Optoelectronics and Microtechnology (ISOM) and Dpto. Ingeniería Electrónica, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)
2. Departamento de Ciencia de los Materiales e IM y QI, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)

Changing the growth rate during the heteroepitaxial capping of InAs/GaAs quantum dots (QDs) with a 5 nm-thick GaAsSbN capping layer (CL) strongly modifies the QD structural and optical properties. A size and shape transition from taller pyramids to flatter lens-shaped QDs is observed when the CL growth rate is decreased from 1.5 to 0.5 ML/s. This indicates that the QD dissolution processes taking place during capping can be controlled to some extent by the GaAsSbN CL growth rate, with high growth rates allowing a complete preservation of the QDs. However, the dissolution processes are shown to have a leveling effect on the QD height, giving rise to a narrower size distribution for lower growth rates. Contrary to what could be expected, these effects are opposite to the strong blue-shift and improvement of the photoluminescence (PL) observed for higher growth rates. Nevertheless, the PL results can be understood in terms of the strong impact of the growth rate on the Sb and N incorporation into the CL, which results in lower Sb and N contents at higher growth rates. Besides the QD-CL band offsets and QD strain, the different CL composition alters the band alignment of the system, which can be transformed to type-II at low growth rates. These results show the key role of the alloyed CL growth parameters on the resulting QD properties and demonstrate an intricate correlation between the PL spectra and the sample morphology in complex QD-CL structures.

• OSTI ID: 22305762
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIMONY COMPOUNDS
ARSENIC COMPOUNDS
CRYSTAL GROWTH
CRYSTAL STRUCTURE
DISSOLUTION
DISTRIBUTION
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INDIUM ARSENIDES
LAYERS
NITROGEN COMPOUNDS
OPTICAL PROPERTIES
PHOTOLUMINESCENCE
QUANTUM DOTS
QUATERNARY ALLOY SYSTEMS
SPECTRA
STRAINS
SURFACE COATING