Self-aligning phenomena of ZnCdSe islands grown by molecular beam epitaxy on GaAs(l10) surface cleaved in ultra high vacuum

Self-organized formation of islands has been investigated for the growth of Zn,,Cd,,Se on the GaAs(ll0) surface cleaved in ultra high vacuum by molecular beam epitaxy. We found, for the first time, phenomena that the self-organized Zn, _,Cd,Se islands aligned in long-range up to several tens of pm on GaAs(ll0) surface. Two types of surface structures were observed, pyramidal-shaped islands and elongated triangular ridges. The islands were selectively grown on the top of the ridges along [l]O] direction. The ridges were presumably caused by the anisotropic in-plane strain relaxation of the epilayers on the (1 IO&oriented substrate. The periodic strain distributions on the ridges are suggested to account for the arrangement of the islands.