Template-Free Liquid-Phase Synthesis of High-Density CdS Nanowire Arrays on Conductive Glass

High-density and single-crystal line CdS nanowire arrays were formed on fluorine-doped tin oxide (FTO)coated soda-lime glass substrates without aid of templates at 220 degrees C. Bi was employed as a catalyst for the low-temperature growth of CdS nanowires via solution-liquid-solid (SLS) mechanism. CdS nanowires were very straight and they were similar to 20-50 nm in diameter and similar to 2-3 mu m in length. CdS nanowires were in highly crystalline wurtzite structure, and their crystal growth direction was [001]. Careful controlling of processing conditions including Bi catalyst size, precursor concentration, and processing temperature was effective to grow thin CdS nanowires by suppressing formation of nanoparticles and radial growth of nanowires. Poly vinyl alcohol (PVA) film covering Bi catalyst layer played a critical role in holding Bi liquid droplets on the substrates during nanowire growth. The potential of CdS nanowire arrays on FTO/glass substrates was demonstrated to be used for organic-inorganic hybrid solar cells.