Quasi-one-dimensional single AlGaAs/GaAs Hall bar quantum wires grown on patterned substrates

Hall bars with widths down to about 250 nm were prepared by overgrowth on patterned GaAs(001) substrates using molecular beam epitaxy. This fabrication method generates a lateral confinement potential determined by AlGaAs barriers. The four-terminal magnetoresistance of a single wire, measured at 1.3 K after illumination, displays the well-known features of quasi-one-dimensional electron systems. We estimate the electron mobility in a ∼250 nm wide wire to be larger than 51 000 cm2/V s at a carrier concentration of 3.3×1011 cm−2.This mobility is comparable to the one measured in a wide reference sample fabricated under identical conditions.