Catalyst-free selective-area MOVPE of semiconductor nanowires on (111)B oriented substrates

We report on a catalyst-free approach for the growth of semiconductor nanowires which is attracting interest as building blocks for nanoscale electronics and circuits. Our approach is based on selective-area MOVPE and nanowires are grown from small circular openings of SiO2, mask defined on (I I I)B-oriented substrates. At optimized conditions, extremely uniform array of GaAs and InGaAs nanowires with diameter of about 200 nm was grown on GaAs and trip substrates, respectively. The nanowires have hexagonal cross-section and are perpendicular to the substrates, indicating that they are surrounded by I I 10) facet sidewalls. By reducing the mask opening size, nanowires with diameter down to 50 nm and length more than 5 mum were successfully formed. Photoluminescence and transmission electron microscopy characterization was also carried out. (C) 2004 Elsevier B.V. All rights reserved.