The growth process of small self-interstitial clusters In (n≤7) in crystalline GaAs was addressed by semi-empirical tight-binding molecular-dynamics technique. The In ground-state structures were found among many possible choices of topological properties and stoichiometric compositions. The stable structure were fully characterised concerning the structural, electronic, energetic, and elastic properties; some remarkable findings emerged concerning, among the others, the stability scenario of the ground-state structures, the possible low-energy reaction paths involved in the growth process, the electrostatic and the elastic capture volumes and the Fermi-level pinning. It was demonstrated that compact geometries were no longer energetically favoured for n≥5 and that the In growth proceeds via capture processes involving either isolated interstitials or di-interstitials. An extended penta-interstitial (I5) ground-state structure was identified as the possible core-basic structure of extrinsic linear defects along the {111} direction of the GaAs lattice.

Nucleation and First-Stage Growth Processes of Extrinsic Defects in GaAs Triggered by Self-Interstitials. F.Gala, G.Zollo: Physical Review B, 2009, 80[17], 174113