In situ ultra high vacuum scanning probe microscopy (SPM) and low-temperatu
re :photoluminescence (PL) studies have been performed on Si-doped self-org
anized InAs/GaAs quantum dots samples to investigate the Si doping effects.
Remarkably, when Si is doped in the sample, according to the SPM images, m
ore small dots are formed when compared with images from undoped samples. O
n the PL spectra, high-energy band tail which correspond to the small dots
appear, with increasing doping concentration, the integral intensity of the
high-energy band tail account for the whole peak increase too. We relate t
his phenomenon to a model that takes the Si atom as the nucleation center f
or QDs formation. (C) 1999 Elsevier Science B.V. All rights reserved.