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New nanocluster to boost thin films for semiconductors


The laboratories of University of Oregon Professor Darren Johnson and Oregon State University Professor Douglas Keszler have worked together to help improve the performance of amorphous semiconductor materials, such as those used in LCD technology. We have also worked to improve the processing of these materials, in particular striving for solution-deposited thin films which use only water in their fabrication, followed by an annealing process. Many current technologies use energy intensive deposition means such as vapor deposition. We in the Johnson lab have successfully made a series of water soluble metal hydroxide clusters, either all gallium tridecameric clusters, or heterometallic gallium indium clusters where we can control the ratios of the two metals. In the Keszler lab, our materials were used as intended, and were successfully used to make both gallium oxide and indium-gallium oxide thin films through the solution deposition of these single-source precursors. With the demonstrated ability to control the metal ratio of indium to gallium at the molecular level in the precursor inorganic clusters, we can therefore precisely control the material content of the resulting films, tailoring the ratio of indium to gallium. The films produced have been very high performing, with electron mobilities higher than that of amorphous silicon. Higher performance semiconductors could ultimately lead to more efficient, higher performance devices, such as LCD displays. Steps have already been taken in this direction, and the groups will continue to work together on making additional precursors and thin film compositions. The nature of both groups’ projects has been greatly enhanced by the collaborative, interdisciplinary aspects of this project, so far culminating in the publication of the results of these studies in the journal Angewandte Chemie, International Edition, (Angew. Chem., Int. Ed. 2008, 47, 9484) a top tier chemistry journal.