High transmittance CdO thin films obtained by the sol-gel method

Abstract CdO thin films have been prepared by the sol-gel technique, from a novel precursor solution based on Cd(OOCCH 3 ) 2 ·2H 2 O, ethylene glycol, glycerol, and triethylamine, on slide glass substrates. The films were annealed in open atmosphere at 200°C and were characterized by UV-VIS spectroscopy, X-ray diffraction and atomic force microscopy. The CdO thin films obtained have a high polycrystalline quality and, outstandingly, they show a transmission of 95% at a wavelength of 600 nm, which increases to virtually 100% from 700 to 1100 nm. The indirect and direct band gap energy values were found to be 2.06 and 2.59 eV, respectively. The resistivity of the films was 2×10 −2 Ω cm.