Variable width and electron density quantum wires in GaAs/AlGaAs with ion‐implanted gates and a surface Schottky gate

Beryllium implants have been used to form p‐n junctions which confine electrons laterally in a GaAs/AlGaAs heterostructure to make high‐mobility quasi‐one‐dimensional wires whose electrical width can be varied by biasing the implanted regions. Incorporation of an additional surface Schottky gate enables the electron density within the wires to be controlled independently. Magnetoresistance measurements have been performed at 1.7 K and the weak‐field boundary‐scattering maxima used to determine the width as a function of both the bias applied to the implanted regions and to the surface gate. The mobility is also calculated and is comparable to that reported for wires of similar dimensions fabricated using high energy ion damage.