GaAs dot-wire coupled structures grown by selective area metalorganic vapor phase epitaxy and their application to single electron devices

Abstract

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 (001) 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.