Synthesis and Characterization of Liquid MOCVD Precursors for Thin Films of Cadmium Oxide

Four novel Cd(C5F6HO2)2·polyether adducts were prepared through simple procedures with stoichiometric quantities of cadmium oxide, hexafluoroacetylacetone C5F6H2O2, and different polyethers. The products were characterized by elemental analysis, X-ray single-crystal analysis, mass spectra, NMR spectra, thermal measurements, and infrared transmittance spectroscopy. X-ray single-crystal data of the Cd(C5F6HO2)2·polyether adducts showed that all the oxygen atoms of the polyether molecules coordinate the cadmium cation. Very mild heating (44−74 °C) resulted in thermal stable, liquid compounds which, in turn, can be easily evaporated. Gas-phase deposition experiments, in a low-pressure horizontal hot-wall reactor, on SiO2 substrates, resulted in CdO films. XRD measurements provided evidence that they consist of cubic, (100)-oriented, crystals. UV−vis spectra showed that the transmittance of as-deposited films in the visible region is about 90%.