Structure, optical, and photocatalytic properties of Cd-doped ZnO microstructures prepared by MOCVD at atmospheric pressure

This work aims to investigate the effect of cadmium dopant concentration on the properties of zinc oxide microstructures grown on silicon substrates by using metalorganic chemical vapor deposition at atmospheric pressure. The XRD patterns confirm the formation of a wurtzite-type crystalline phase of zinc oxide. The photoluminescence spectra of the studied ZnO microstructures consist of several bands, including a violet band (3.24 eV), blue band (2.8 eV), and yellow band (2.1 eV). The blue band was observed only for Cd-doped ZnO microstructures and was absent for undoped ZnO microstructures. ZnO microstructures grown with 1, 2.5, and 10 wt.% of Cd in the precursor mixture exhibited the best photocatalytic efficiency (over 70% degradation of Methyl Orange dye within 180 min). The higher reaction rate constant was observed for Cd-doped ZnO microstructures, for which the contribution of the blue band in the whole photoluminescence spectrum lies within 30…40% and the contribution of the violet band is close to 20%. The obtained results demonstrate that Cd-doped ZnO microstructures exhibit attractive photocatalytic activity and can be used for the development of effective photocatalysts.