Fabrication of Small Nanowires

I will discuss a versatile template-technique[1] aimed at the fabrication of nanowires with lateral width below 10 nm. Employing a MBE grown GaAs/AlGaAs/GaAs sample on whose cleaved, surface we spin PMMA, electron beam lithography and metal evaporation are used to define an etching mask followed by selective etching of the GaAs over AlGaAs. The etching leaves a relief onto which the nanowire metal is deposited and the metallic etch mask is used to electrically contact the nanowire. With this technique we have been able to fabricate a fully functional AuPd wire 40 nm wide and 20 micrometer long on which we performed magneto-resistance measurements. With more complex MBE structures, unusual geometries may be realized down the road.