InGaAs quantum dots on GaAs(311)B substrates confined in AlGaAs barrier layers

We investigated the growth of QDs on AlGaAs/GaAs(3 1 1)B by atomic hydrogen assisted molecular beam epitaxy. In the growth of QDs directly on AlGaAs, the QDs size fluctuation increased with increasing Al composition of the Al GaAs underlying layer. However, the uniformity of QDs size and the ordering were improved by introduction of a thin GaAs spacer layer. It was conclude d that there is a strong interaction between the InGaAs-strained and underl ying layers. The strong photoluminescence intensity of QDs confined in AlGa As with GaAs spacer layers was maintained up to room temperature. Hence, th e carrier collection efficiency into the QDs was improved and the escape of carriers from the QDs was suppressed by introducing higher potential AlGaA s barrier layers. (C) 2001 Elsevier Science B.V. All rights reserved.