Effects of growth interruption during the formation of InAs/GaAs self-assembled quantum dots grown by molecular beam epitaxy

We have investigated the structural and optical characteristics of InAs quantum dots (QDs) during growth interruption using conventional solid source molecular beam epitaxy. Size of the QDs decreased and size uniformity improved by the introduction of a growth interruption. The average height of the QDs increased while the average width decreased as the interruption time was extended from 0 to 32 s. At longer than 32 s, the average height became almost saturated, but the standard deviation of the height was decreased. These results showed that the indium adatoms around the bottom of the QDs were moved to the top of them. And, self-limiting behavior occurred when the interruption time was longer than 32 s. Low-temperature photoluminescence (PL) emissions from the capped QD structure were shifted to red-side by increasing the average height. On the other hand, both intensity and symmetry of the PL peak were improved because, the height of the QD became uniform by growth interruption. (C) 2003 Elsevier Science Ltd. All rights reserved.