Photoluminescence and structural properties of self-assembled InAs quantum
dots, grown on AlyGa1-yAs, are studied for y = 0, 0.3, and 0.5. A maximum b
lue shift of 150 meV for the ground state: emission energy is determined wi
th increasing y for the samples as grown, Increased surface density and siz
e inhomogeneity is observed for growth on AlGaAs compared to growth on GaAs
. Rapid thermal annealing at temperatures ranging from 550 to 850 degreesC
is used to further increase the ground state emission energy with respect t
o the as grown samples. We find a shift up to a maximum emission energy of
1.9 eV for InAs quantum dots (QDs) embedded in Al0.3Ga0.7As compared to 1.4
eV for GaAs matrix material. To combine the higher spectral shift by annea
ling for InAs QDs embedded in AlGaAs with the lower dot density for the gro
wth on GaAs, favored for single dot spectroscopy, we investigated InAs QDs
grown on AlGaAs separated by 2 ML GaAs. For these samples we observe a maxi
mum shift by annealing up 1.4 eV and intense room temperature PL.