Formation of self-assembled Ga-rich droplet chains on GaAs (100) patterned by focused ion beam

Controlled positioning and ordering of uniform self-assembled droplets on a patterned GaAs (100) substrate is demonstrated using a Ga+ focused ion beam. The arrangement of the droplets into an array of droplet chains is induced by changes in the surface morphology during irradiation as a function of sputtering time. Energy dispersive x-ray spectroscopy reveals that the droplets are Ga-rich. The patterned surface may be of interest for plasmonic studies and may find application as a template for site-specific epitaxial growth of unstrained quantum dot chains utilizing local droplet etching and droplet epitaxy techniques.