Realization of Unidirectional Planar GaAs Nanowires on GaAs (110) Substrates

A self-aligned unidirectional planar GaAs nanowire (NW) array is realized by growing on (110) GaAs substrates through the Au-catalyzed vapor-liquid-solid mechanism. All NWs on (110) substrates propagate along the [00-1] direction, yielding planar NWs with trapezoidal cross sections where the top surface and sidewalls are identified by micro X-ray diffraction analysis to be [110], [010], and [100] facets, respectively. Depletion-mode long-channel metal-semiconductor field-effect transistors using these [00-1] GaAs NWs as channels exhibit well-defined dc output and transfer characteristics, confirming the high material quality of the NWs. Completely ordered site controlled arrays of planar NWs are demonstrated by growing on (110) substrates with Au catalyst nanoparticles patterned using electron beam lithography.