Abstract
The authors report the molecular beam epitaxial growth and the structural and optical characterizations of self-assembled/catalyst-free GaAs nanodisks on SiO2 masked Si(100) patterned substrates. Pure zincblende GaAs nanodisks with precise positioning and low defect density are demonstrated by selective area epitaxy. The influence of the growth temperature and deposition duration is investigated. Excellent morphological and structural properties are characterized by scanning electron microscopy and cross-sectional transmission electron microscopy. Defects in the epilayers are reduced by strain relaxation through facets formation and by a lateral overgrowth scheme atop the SiO2 mask which is corroborated by microRaman spectroscopy. In particular, the authors show how the material quality contributes to excellent optical properties observed by microphotoluminescence spectroscopy from 77 K to room temperature. (C) 2014 American Vacuum Society.