Characteristics of ZnO:Cr thin films deposited by spray pyrolysis

Chromium-doped zinc oxide thin films were deposited using the spray pyrolysis technique. In all cases 15 at. % of chromium in solution was used. Under diluted HCl, a low etching rate in ZnO:Cr thin films is obtained, as compared to undoped ZnO. As-deposited and vacuum-annealed films show a high resistivity. X-ray diffraction spectra show no extra phases present. A low incorporation efficiency of chromium into the ZnO films is observed, and less than 1 at.% chromium is present in the films and (002) preferential growth is observed in all cases. High transmittance is obtained, which makes films adequate for transparent and protective coatings.