We report the fabrication of GaAs/AlGaAs quantum well wires using implantation of As at 45 keV to induce quantum well intermixing. The intermixing process was first characterized giving optimized annealing parameters of 875 °C for 30 s and an implantation dose of 1×1013 cm-2. Wire widths from 35 to 1000 nm were defined using e-beam lithography followed by lift-off. Photoluminescence spectra from the lateral wells and barriers were observed from samples with wires as narrow as 50 nm. The energies of the lateral wells were found to remain constant for wire widths between 1000 and 150 nm, and start to shift significantly towards high energy for 80 nm wires, the signal from the lateral well eventually merging with that from the lateral barrier for 35 nm wires. An intermixing radius of about 17 nm was estimated for the process. Photoreflectance measurements were also carried out on these wire samples, showing that the wires appear to have a parabolic lateral potential and clear interwire coupling was observed from samples with barriers narrower than 50 nm. © 1998 American Institute of Physics.