Size reduction of self assembled quantum dots by annealing

Quantum dots in the materials systems InPrGaAs and InPrGa0.5In0.5P were grown at 6008C by low pressure MOVPE in the Stranski–Krastanow growth mode and annealed under PH3rH2at growth temperature. AFM investigations of free standing islands InPrGaAs.show a continuous decrease in height from 19 to 7 nm after 30 min annealing. Photolumines- cence measurements on the overgrown dot samples InPrGa0.5In0.5P.show a shift of the quantum dot emission peak towards higher energies with an increase in annealing time. The proposed explanation relies on exchange reactions between the islands and the wetting layer, as well as alloying between the wetting layer and the underlying substrate due to interdiffusion. q1998 Elsevier Science B.V. All rights reserved.