Structural and optical changes in GaAs/InAs/GaAs structure induced by thermal annealing

Self-organized InAs quantum dots sheets are grown on an GaAs[100] substrate and capped by 80 nm GaAs layer with molecular beam epitaxy. Samples were annealed and characterized with Raman spectra, transmission electron microscopy (TEM) and photoluminescence (PL). The Raman spectra indicates arsenic clusters in the GaAs capping layer. The TEM analysis revealed the relaxation of strain in some InAs islands with the introduction of the network of 90/spl deg/ dislocations. In addition, the structural changes also lead to the changes of the PL spectra from the InAs islands. Their correlation was discussed. Our results suggest that annealing may be used to intentionally modify the properties of self-organized InAs islands on GaAs.