The growth of InGaAs/GaAs quantum dots (QDs) emitting around 1.3 mum by low-pressure metal-organic vapor-phase epitaxy has been studied by transmission electronic microscopy and photoluminescence spectroscopy. Adjusting the encapsulating GaAs thickness deposited on the QDs before the temperature ramping step from the low QDs growth temperature to the higher barriers growth temperature allows the desorption of the dislocated clusters formed simultaneously with the optically active coherent QDs. The extended defect-free QDs array obtained by this method presents an improved photo luminescence efficiency, and is suitable for multiple arrays stacking, (C) 2002 Elsevier Science B.V. All rights reserved.