Pattern transfer to GaAs substrates and epitaxial growth of GaAs nanostructures using self-organized porous templates

GaAs nanostructures were grown on patterned GaAs (111) B substrates with molecular beam epitaxy. Nanopatterns were achieved by patterning a thin film of silicon dioxide (SiO2) grown on the substrate surface with a self-organized porous alumina template. Growth of patterned nanostructures took place through the holes in the SiO2 film. The authors obtained two kinds of nanostructures: nanopillars and nanodots. The majority of nanopillars had two kinds of tops, i.e., hexagonal flat top and pyramidal top, as observed with a scanning electron microscope. High resolution transmission electron microscopy studies showed epitaxial relationships between the nanostructures and the substrates. Photoluminescence measurements of nanopillars showed the photoluminescence peak shifted to a higher energy compared to films grown under the same condition.