Improved optical properties of InAs quantum dots grown with an As2 source using molecular beam epitaxy

We demonstrate the effects of using an As2 source to fabricate self-organized InAs∕GaAs quantum dot (QD) structures. QDs grown with an As2 source have narrower photoluminescence (PL) linewidths and higher PL intensities than those grown with an As4 source at high growth rates. The density of QDs grown with an As2 source is smaller, and the dot size larger than those of QDs grown with an As4 source. The coalescence of QDs is reduced under an As2 source, resulting in improved optical properties. These results are thought to result from the difference in the surface migration of In atoms and the surface structures under As2 and As4 sources.