Controlled growth of InAs nanowires on engineered substrates

We demonstrate the Au-assisted growth of semiconductor nanowires on different engineered substrates. Two relevant cases are investigated: GaAs/AlGaAs heterostructures capped by a $50 {\rm nm}$-thick InAs layer grown by molecular beam epitaxy and a $2 {\rm \mu m}$-thick InAs buffer layer on Si(111) obtained by vapor phase epitaxy. Morphological and structural properties of substrates and nanowires are analyzed by atomic force and transmission electron microscopy. Our results indicate a promising direction for the integration of III-V nanostructures on Si-based electronics as well as for the development of novel micromechanical structures.