Thermal annealing of GaSb quantum dots in GaAs formed by droplet epitaxy

We investigate effects of annealing on GaSb quantum dots (QDs) formed by droplet epitaxy. Ga droplets grown on GaAs are exposed to Sb molecular beam and then annealed at Ta=340–450°C for 1min to form GaSb QDs. An atomic force microscope study shows that with the increase of Ta, the average diameter of dots increases by about 60%, while their density decreases to about 1/3. The photoluminescence (PL) of GaSb QDs is observed at around 1eV only for those samples annealed above Ta=380°C, which indicates that the annealing process plays an important role in forming high quality GaSb QDs.