Top-down fabrication of semiconductor nanowires with alternating structures along their longitudinal and transverse axes

A top-down approach combining multiple lithographic steps and anisotropic chemical etching processes to produce GaAs nanowires with controlled properties along their longitudinal and transverse axis is described. The arrays of GaAS nanowires can conveniently processed by photolithography and etching to generate GaAs wires with complex structures. GaAs wire arrays are prepared by anisotropically etching a GaAs wafer patterned with mask stripes. When the stripes are surrounded by mask material, chemical etching produces GaAs wires with ends that connect to the parent wafer. These connection points pin the GaAs wires at their ends, which hold the wires in the positions defined by the pattern of mask stripes. The approach can also be used to tune the cross section of GaAs nanowires from simple triangular to complex irregular profiles.