Aqueous Synthesis of ZnO Rod Arrays for Molecular Sensor

Abstract

ZnO rod arrays were successfully fabricated on fluorine-doped tin oxide substrates without seed layers and high temperature annealing. ZnO was crystallized in aqueous solutions to form hexagonal cylindrical rods on the substrates directly. The rods elongated along the c-axis and stood perpendicular to the substrates. The rod arrays showed only a 0002 X-ray diffraction peak, indicating a high c-axis orientation. The rods were 100−120 nm in diameter and 300−400 nm in length. The rod arrays had spaces of 100−1000 nm surrounded by rods. They maintained their adhesion during rinse under running water due to direct crystallization on the substrates. The rod arrays covered with dye had incident photon-to-current conversion efficiency of 3.2% under 0.7 mW lasers. Signal-to-noise ratio reached 53. The rod arrays on FTO substrates may be useful for biomolecule sensors and dye-sensitized solar cells.