Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


Condensed Matter

J. Korean Phy. Soc. 2005; 46(4): 985

Published online April 15, 2005

Copyright © The Korean Physical Society.

Effects of a Cap Layer on the Confined Sublevels in Near-Surface InAs/GaAs Quantum Dots

S. J. Lee, J. C. Park, J. O. Kim, S. K. Noh and J. W. Choe


We have investigated the effects of the potential barrier on the confined sublevels observed in the photoluminescence (PL) emission spectra of InAs quantum dots (QDs) capped by an ultra-thin GaAs layer. The PL peak energy of normal InAs QDs covered by a sufficiently thick GaAs layer remains constant as $sim$ 1.11/1.03 eV (15/300 K). For QD systems with cap layers thinner than 10 nm, however, red-shift and blue-shift phenomena in the emission energy are observed above and below, respectively, a critical coverage of 5 nm, which is approximately the same as the average QD height. The red shift and the blue shift can be explained, respectively, by changes in the strained potentials of the GaAs interfaced with the InAs layer and in the band bending of the ultra-thin GaAs potential barriers near surface.\