Growth of InGaAs/GaNAs strain-compensated quantum dot superlattice on GaAs (3Â 1Â 1)B by molecular beam epitaxy

We have studied the structural and optical properties of 10 stacked layers of self-organized In0.4Ga0.6As quantum dots (QDs) grown on GaAs (3 1 1)B substrates by atomic hydrogen-assisted radio frequency (RF)-molecular beam epitaxy. A 40 nm-thick GaN0.007As0.993 dilute nitride, which is used to cover each QD layer acts as a strain-compensation layer (SCL). The density of strain-compensated In0.4Ga0.6As QDs on GaAs (3 1 1)B can be controlled between 2×1010 and 1×1011 cm−2 by simply changing the growth temperature. Closely spaced In0.4Ga0.6As QDs on GaAs (3 1 1)B shows an ordered structure, in which we observe clear peaks in the two-dimensional fast Fourier transformation image. The temperature dependence of photoluminescence (PL) spectra shows a narrower linewidth over the whole temperature range 30−300 K for strain-compensated QDs owing to better uniformity in the QD size.