We describe a method for fabricating GaAs dot arrays and dot-wire coupled structures having periodic nanofacets which uses selective area metalorganic vapor phase epitaxy. First, a thin GaAs buffer layer and an AlGaAs layer are grown on a masked substrate having wirelike openings with periodic width modulation. The width of AlGaAs wirelike structure is naturally squeezed by the periodic combination of nanofacets, and its top ͑001͒ surface is partially isolated by a self-limited region. Next, an AlGaAs/GaAs quantum well structure is fabricated on the substrate to form dots on the narrower top terraces, wires on the wider terraces, and ridge wires in the self-limited region. Cathodoluminescence images clearly showed dot arrays and dot-wire coupled structures were formed using this method. A single electron transistor with the same structure was also fabricated, and clear Coulomb blockade oscillation was observed. We also describe single electron tunneling devices with these dot arrays and dot-wire coupled structures.

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We describe transport measurements in a novel dual-gated single electron transistor (SET) based on a quantum dot (QD) fabricated by selective area (SA) growth of metalorganic vapor phase epitaxy (MOVPE). We observed, for the first time, clear Coulomb oscillations fabricated in combination with direct growth and lithographically defined metal gates, and achieved nearly independent control of the QD potential and the tunneling barrier height. We also were able to observe a signature of Kondo resonance when the coupling between leads and a quantum dot was sufficiently strong. (This article is published in Physica E vol.13, No. 2-4, pp.687-690 (2002).)