PUB - Publikationen an der Universität Bielefeld

A process sequence enabling the large-area fabrication of nanopillar-patterned semiconductor templates for selective-area heteroepitaxy is developed. Herein, the nanopillar tops surrounded by a SiNx mask film serve as nanoscale growth areas. The molecular beam epitaxial growth of InAs on such patterned GaAs ( 111 )A templates is investigated by means of electron microscopy. It is found that defect-free nanoscale InAs islands grow selectively on the nanopillar tops at a substrate temperature of 425 ?. High-angle annular dark-field scanning transmission electron microscopy imaging reveals that for a growth temperature of 400 ?, the InAs islands show a tendency to form wurtzite phase arms extending along the lateral & lang; 11 (2) over bar & rang; directions from the central zinc blende region of the islands. This is ascribed to a temporary self-catalyzed vapor-liquid-solid growth on { 11 1 over bar } B facets, which leads to a kinetically induced preference for the nucleation of the wurtzite phase driven by the local, instantaneous V/III ratio, and to a concomitant reduction of surface energy of the nanoscale diameter arms. Published under an exclusive license by AIP Publishing.