Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


Condensed Matter

J. Korean Phy. Soc. 2005; 46(6): 1396

Published online June 15, 2005

Copyright © The Korean Physical Society.

Growth-Mode Transition Controlled by the Substrate Temperature in InAs/GaAs Quantum-Dot Ensembles

S. J. Lee, J. O. Kim, Y. G. Kim, S. K. Noh, Y. H. Ryu, S. M. Choi and J. W. Choe


We report a growth-mode transition observed in the optical and the structural characteristics of self-assembled InAs quantum-dot (QD) ensembles with different size distributions controlled by the substrate temperature. The photoluminescence spectra and the atomic force microscope images show that the QD ensembles change from a small-size mode to a large-size one via a bimodal phase appearing at a mode-transition temperature of 490 $^circ$C. On the bases of the variations of the emission energy and the apparent dimension, two kinds of growth mechanisms of adatom diffusion and island migration are suggested for the island ripening and the dynamic coalescence of QDs below and above the mode-transition temperature. Finally, we proposed a schematic model illustrating the size evolution of QDs.