InAs Island Formation Aligned along the Steps on a GaAs(001) Vicinal Surface

InAs island formation on a GaAs(001) substrate misoriented by 1 degrees toward the [110] direction was investigated by scanning tunneling microscopy. On a 2.0ML InAs-deposited GaAs surface, three-dimensional islands were observed; some of the islands were aligned along the [1 ($) over bar 10] direction. That is, the islands were selectively formed at steps running relatively straight along the [1 ($) over bar 10] direction on the GaAs surface. These results show the possibility of controlling the arrangement of InAs islands on a surface by controlling the step structure on the surface, which induces selective island formation at the steps.