Catalyst-free patterned growth of well-aligned ZnO nanowires on ITO substrates using an aqueous solution method and lithography process

Well-aligned ZnO nanowires were directly grown on indium tin oxide (ITO) glass substrates coated with ZnO seed layers via an aqueous solution route. During the growth process, the ZnO seed layer played the role of providing nucleation sites in the selective growth of the well-aligned ZnO nanowires. The ZnO seed layer was deposited on the substrate using pulsed laser deposition (PLD) at room temperature. The uniform ZnO nanowires were grown in aqueous solution containing zinc nitrate hexahydrate and hexamethylenetetramine at 90°C. The diameter and length of ZnO nanowires were approximately 80 nm and 2.2 μm, respectively. The selectively patterned ZnO nanowires were fabricated on the ITO-coated substrates by combining this simple solution method and a conventional photolithography process.