SUPPRESSION OF OSTWALD RIPENING IN IN0.5GA0.5AS QUANTUM DOTS ON A VICINAL (100) SUBSTRATE

A comparative study of the morphology of self-assembled In0.5Ga0.5As quantum dots grown by atmospheric pressure metal-organic chemical vapor deposition on the exact ~100! and 2°-off ~100! GaAs substrates as a function of growth interruption time ~0–1200 sec! is presented. The dots are randomly distributed on the exact ~100! substrate, whereas the dots on the 2°-off ~100! substrate are aligned along multiatomic steps. As the interruption time t is increased, the density of dots on the exact ~100! substrate decreases and their average volume progressively increases with ;t dependence, indicating a regular Ostwald-ripening process. By contrast, the average volume of dots on the 2°-off ~100! substrate saturates for interruption times over 200 sec and shows obvious suppression of ripening. In particular, the size of dots on the 2°-off ~100! substrate is limited within the atomic terrace width (;55 nm). These results demonstrate that the density and size of dots could be controlled by interruption time and substrate miscut angle. @S0163-1829~98!04416-6#