A comprehensive study of the effect of <Emphasis Type="Italic">in situ</Emphasis> annealing at high growth temperature on the morphological and optical properties of self-assembled InAs/GaAs QDs |
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Authors: | N Halder R Rashmi S Chakrabarti C R Stanley Miriam Herrera and Nigel D Browning |
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Institution: | (1) Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, Maharashtra, India;(2) Department of Electronics & Electrical Engineering, Rankine Building, Oakfield Avenue, Glasgow, G12 8LT, UK;(3) Department of Chemical Engineering and Materials Science, University of California-Davis, 1153 Kemper Hall, One Shields Avenue, Davis, CA 95616, USA |
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Abstract: | We investigate the effect of in situ annealing during growth pause on the morphological and optical properties of self-assembled InAs/GaAs quantum dots (QDs).
The islands were grown at different growth rates and having different monolayer coverage. The results were explained on the
basis of atomic force microscopy (AFM) and photo-luminescence (PL) measurements. The studies show the occurrence of ripening-like
phenomenon, observed in strained semiconductor system. Agglomeration of the self-assembled QDs takes place during dot pause
leading to an equilibrium size distribution. The PL properties of the QDs are affected by the Indium desorption from the surface
of the QDs during dot pause annealing at high growth temperature (520°C) subsiding the effect of the narrowing of the dot
size distribution with growth pause. The samples having high monolayer coverage (3.4 ML) and grown at a slower growth rate
(0.032 ML s−1) manifested two different QD families. Among the islands the smaller are coherent defect-free in nature, whereas the larger
dots are plastically relaxed and hence optically inactive. Indium desorption from the island surface during the in situ annealing and inhomogeneous morphology as the dots agglomerate during the growth pause, also affects the PL emission from
these dot assemblies. |
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Keywords: | PACS" target="_blank">PACS 81 30Fb 68 35 78 67 Hc 73 21 La 78 55 Cr |
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