Bismuth-Assisted CdSe and CdTe Nanowire Growth on Plastics

A modified chemical vapor deposition process wits used to synthesize long (> 10 mu m), 20-60 nm diameter CdSe and CdTe nanowires (NWs) at low temperatures on plastic. The approach applies synthetic strategies developed during the growth of solution-based semiconductor NWs. Namely, a thin Bi film is employed to induce NW growth at temperatures as low its similar to 300 degrees C on polyimide. This plastic is flexible, semitransparent, and possesses excellent chemical stability. Resulting wires have subsequently been characterized using various techniques, including scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy, NW formation appears to follow a vapor-liquid-solid (VLS) mechanism with Bi nanoparticles inducing directional growth. The length, width, and overall density of the wires can be modified by varying the growth temperature, Bi film thickness, as well its the introduced precursor metal:chalcogen stoichiometry. Additional Studies were conducted to grow wires on other substrates such as silicon, glass, indium-tin-oxide coated glass coverslips, and Teflon. This study highlights the ability to synthesize II-VI NWs at low temperatures on various materials including plastics and raises the possibility of eventually developing conformal NW solar cells.