Sub-20 nm island self-organisation stimulated by spatially periodic laser exposure in the GaAs/InGaAs/GaAs epitaxial system

Abstract

Four-beam laser interference is shown to stimulate the self-organisation of periodic two-dimensional arrays of nanoislands on the surface of GaAs/InGaAs/GaAs epitaxial structures. (Self-organisation is here taken to mean processes that determine the island size.) The island size distribution has two well-defined maxima. The smaller islands (∼5 nm) form inside each heat-affected zone, and the larger islands (∼15 nm), at the periphery of such zones. The island width is a factor of 20 — 60 smaller than the standing wave period, which can be accounted for in terms of the elastic stress on the surface of the epitaxial film.