抄録
We found that two types of self-organized InGaAS quantum dots (QDs) appear on GaAs (001) substrates by controlling the growth temperature and the cycle number in alternate source supply metalorganic vapor phase epitaxy (MOVPE). The two types of QDs are well distinguished each other by photoluminescence (PL). One type of QD (Type A) exhibits broad PL around 1.2μm. The other type of QD (Type B) exhibits sharp PL around 1.3μm. At low temperature, the source supply first forms Type A QDs and the following source supply transfers Type A QDs to Type B QDs whose size is much larger than that of Type A QDs. :When the temperature is sufficiently low, the transition induces formation of stacking faults. We also investigated the multistacking growth of these QDS and found a significant increase in the Type B QD density in the bottom layer compared to the singlestacking growth. These results suggest that the three-dimensional condensation of atoms in wetting layers occurs during the formation of Type B QDs.
