Si doping effect on self-organized InAs/GaAs quantum dots

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.