Optical and Photoconductive Response of CuO Nanostructures Grown by a Simple Hot-Water Treatment Method

In this work, we report the fabrication and characterization of copper(II) oxide (CuO) nanoleaf structures (NS) grown on Cu sheets by a facile hot-water treatment (HWT) method without using catalyst materials. In addition, simple photoconductive devices based on asprepared CuO nanoleaves were fabricated to study the optical and photocurrent response of CuO NSs. Scanning electron microscopy images revealed the formation of uniform and dense nanoleaves morphology of CuO on Cu sheets. X-ray diffractometer patterns indicated that synthesized nanostructures have a monoclinic CuO structure. Furthermore, X-ray photoelectron spectroscopy results demonstrate the formation of the Cu-O chemical bond which confirmed the formation of the CuO phase. For the fabrication of the photoconductive devices, the CuO/Cu samples were coated with an aluminum-doped ZnO (AZO) shell by sputter deposition at room temperature. CuO NSs show high-broadband ultraviolet/visible spectroscopy (UV/vis) absorbance with marked enhancement after AZO coating. Current density-voltage (J-V) measurements show that AZO/CuO/Cu devices exhibit a photocurrent density response of 9.65 +/- 0.43 mu A/cm(2) with a rise time of 0.195 s and decay time of 0.192 s. They also indicate a Schottky contact between p-type CuO NSs and the Cu substrate. Photocurrent increases and rise time and decay time decrease with an applied forward bias (e.g. similar to 19.00 mu A/cm(2) at 1.0 V with a rise time of , similar to 0.100 s and decay time of 0.096 s). Optical band gap of CuO NSs was calculated to be 1.44 +/- 0.13 eV, by the analysis of Tauc's plot. These results indicate that our photoconductive devices based on CuO NSs prepared by FIVVT can achieve high light absorption and good photocurrent response for optoelectronic applications.