CdO thin films: a study of their electronic structure by electron spin resonance spectroscopy

The Cd(C5F6HO2)2 polyether adducts were used in MOCVD experiments of cadmium oxide, on optical transparent SiO2 substrates. Very mild heating (44-74 8C) resulted in, thermal stable, liquid compounds that can be easily evaporated. XRD measurements provided evidence of cubic highly textured CdO(1 0 0) films. The surface atomic composition was investigated by XPS analysis. UV-vis spectra showed that the transmittance of as-deposited films in the visible region is about 90%. Resistivity measurements of CdO thin films showed that they are highly conducting. ESR analysis suggests the presence of Cd+ ions, on the site of Cd2+, arising from polaronic self-trapping of electrons introduced by oxygen deficiency at Cd2+ sites to generate localised 5s1 states.