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%.