In this study, vertically well-aligned CuO nanorods were grown on fluorine-doped tin oxide (FTO) substrate by a modified chemical bath deposition (M-CBD) process with various volume ratios of a copper acetate (Cu(OAc)(2)) aqueous solution and a 25% NH3 solution without any template and surfactant. The well-aligned CuO nanorods showed a growth rate as high as 127 nm/min. In addition, (020) directional growth was confirmed by X-ray diffraction measurements. The photoelectrochemical properties of the CuO nanorods as a photoelectrode material were also measured in an aqueous electrolyte solution (1 M KOH) under 1-sun illumination conditions (1.5 AM filter, 100 mW/cm(2)) using a potentiostat. A maximum photocurrent density of 0.88 mA/cm(2) at -0.55 V (vs. SCE) was obtained for the CuO-nanorod photoelectrode fabricated in this experiment. (C) 2014 The Electrochemical Society. All rights reserved.