Direct Growth of Copper(II) Oxide (CuO) Nanostructures Films via One-Step Chemical Bath Deposition by pH Variation

摘要

An aqueous solution was prepared by mixing the copper(II) sulfate pentahydrate (CuSO_4), lactic acid, sodium hydroxide (NaOH) and de-ionized (DI) water. Direct deposition of copper(II) oxide (CuO) nanostructures films on glass substrates was achieved by a simple, inexpensive and one-step chemical bath deposition method. The pH of the solution was varied at 11.7, 12.0, 12.3 and 12.6 and immersed at low temperature (90°C). The influences of the pH solution towards the surface topography, morphology and thickness were investigated by a field emission scanning electron microscopy (FESEM), an atomic force microscope (AFM) and a surface profiler. Meanwhile, an X-ray diffractometer (XRD) was used to examine the structural properties of CuO films. The optical properties were measured by a UV-Vis spectroscopy. It was found that the grain size of the films decreases and the surface becomes smoother and more uniform by increasing the pH solution. The CuO nanostructures have high crystallinity with monoclinic structure which is preferentially grown along (111) and (200) directions. Therefore, the film has great potential for gas sensor device.