Organic vapor-jet-based route for solvent-free additive formation of oxide semiconductors

We demonstrate a novel solution-free technique which can be used to print metal oxide patterns without masks by adopting an organic vapor jet printing (VJP) method. To avoid the high deposition temperatures required for metal oxide vaporization, metal-organic compounds are first jet-printed as metal-oxide precursors and converted into metal oxides by a photo-conversion process. As an example, we show that indium oxides can easily be prepared from jet-printed films of indium acetylacetonate upon photo-conversion; the effectiveness of which is supported by X-ray photoelectron spectroscopy (XPS) showing a reduction of the carbon portion associated with the alkyl chains of the precursors. A carrier mobility of 4.5 cm2/V·s and an on/off ratio of 105 are demonstrated in the oxide thin-film transistors based on indium oxides prepared by the proposed method, illustrating the potential usefulness of this process in electronic device fabrication.