Synthesis of GaAs quantum dots on Si-layers on AlGaAs films grown on GaAs(100)

In this work we report a novel method for obtaining GaAs quantum dots (QDs) by molecular beam epitaxy (MBE) on an AlGaAs underlying film. We propose to use a Si monolayer (ML) grown on AlGaAs in order to induce a three-dimensional nucleation during the GaAs overgrowth. We observe that when 2.1 MLs of GaAs are grown on 1 ML of Si, the GaAs is self-assembled in islands. Islands of 15-A˚ height and a lateral size of 200 A˚ were clearly observed. 77 K photoluminescence and photoreflectance spectra of capped GaAs dots showed an additional signal at ∼1.88 eV, presumably related to the islands emission, thereby verifying an efficient quantum confinement. [Copyright &y& Elsevier]