Quantum dots based on InAs/GaAs are perspective structures for active zones of lasers and optical amplifiers used for data transmission via optical fibre waveguides.
We prepare InAs/GaAs quantum dots using Stranski-Krastanow growth mode in MOVPE (Metal-Organic Vapour Phase Epitaxy) laboratory of Semiconductor department.
A time-resolved record of anisotropy of reflectance during InAs quantum dot growth..
We managed to find a new technique for monitoring of InAs quantum dot formation in an MOVPE reactor. We found that it is possible to obtain information about growth rate of InAs strained layer (maximum at 1 monolayer of InAs) by means of the detection of reflectance anisotropy of epitaxial surface at 4.2 eV. Furthermore, it is possible to observe in real-time when quantum dots start to be formed and when their development is terminated [1]. In this manner, we are able to optimise technological parameters more easily during quantum dot growth, i.e. to prepare structures with better parameters – suitable wavelength and high intensity of photoluminescence – and simultaneously reduce costs of preparation of these structures.
An AFM image of quantum dots.
[1] A. Hospodková, J. Vyskočil, J. Pangrác, J. Oswald, E. Hulicius, K. Kuldová, Surface processes during growth of InAs/GaAs quantum dot structures monitored by reflectance anisotropy spectroscopy, Surf. Sci. 604 (2010) 318 - 321.
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