LAUSR

Abstract We have investigated the spatial evolution of ( n × 3 ) surface reconstructed areas during the molecular beam epitaxial growth of InAs–GaAs(001) by using ab initio-based calculation and in situ observation, in order to understand the mechanism of consequent QD nucleation. Statistical analysis of ( n × 3 ) -reconstructed morphology reveals that the fraction of ( 8 × 3 ) -reconstructed areas, as well as those of ( 4 × 3 ) and ( 6 × 3 ) , appears and decreases in the later stage of the growth. This behaviour is consistent with the result of our ab initio-based calculation incorporating chemical potentials of source materials in the gas phase. In contrast, fragmented ( 2 × 3 ) areas remain throughout the InAs growth as potential QD nucleation sites.