Large-scale synthesis and in situ functionalization of Zn3P2 and Zn4Sb3 nanowire powders

A simple method for the large-scale synthesis of gram quantities of compound semiconductor nanowires without the need for any external catalysts or templates is presented. This method is demonstrated using zinc phosphide (Zn3P2) and zinc antimonide (beta-Zn4Sb3) nanowires as example systems. Large-scale synthesis of Zn3P2 and Zn4Sb3 nanowire powders was accomplished using a hot-walled chemical vapor deposition chamber by transporting phosphorus and antimony, respectively, via the vapor phase onto heated zinc foils. The zinc foils were rolled concentrically into coils to maximize the substrate surface area, and consequently, the nanowire yield. Using this method, 250 mg of Zn3P2 nanowires were obtained on 480 cm(2) of zinc foil in a span of 45 minutes. Furthermore, a process of exposing the synthesized nanowires to a vapor of organic functional molecules immediately after their synthesis and before their removal from the vacuum chamber was developed to obtain large quantities of surface functionalized nanowire powders. This in situ vapor-phase functionalization procedure passivated the nanowire surfaces without adversely affecting their morphology or dimensions. Our studies revealed that both 4-aminothiophenol and 3-propanedithiol functionalized Zn3P2 nanowires were stable over a 120 day duration without any agglomeration or degradation. This method of mass producing nanowires can also be extended to other binary semiconductors.