Height-controlled nanowire branches on nanotrees using a polymer mask

Abstract

The production of complex three-dimensional dendritic structures is an important step inthe application of semiconductor nanowires. One promising method for achieving this is thesequential seeding of multiple generations of epitaxial nanowires using metal seed particles.However, it is difficult to control and predict the position of second and higher generationnanowires with respect to the first generation. Here we demonstrate a procedure forcontrolling the position of second-generation epitaxial nanowire branches on verticallyaligned nanowire trunks. This method uses a spun-on polymer layer that masksfirst-generation wires to a specified height, preventing the growth of nanowire branches atlower positions as well as new nanowire growth on the substrate. This methodappears not to be dependent on the materials or growth system (in this caseMOVPE-grown GaP is demonstrated), and hence is likely to be applicable to avariety of materials systems and growth procedures using metal seed particles.