David Mitzi

Abstract: The effort to identify low-cost, high-throughput solution-based deposition techniques for thin-film field-effect transistors (TFTs), solar cells and related electronic devices has generated substantial interest in recent years, as a result of new applications potentially enabled by the alternative technologies (e.g., flexible displays, electronic newspapers, smart cards/fabric, large-area solar cells).

While much work in this field has focused on organic semiconductors, this talk will address a solution-based approach for processing inorganic metal chalcogenide semiconductors that relies on the low-temperature decomposition of highly soluble hydrazine-based metal chalcogenide precursors. The resulting metal chalcogenide films may be only a few unit cells thick, with large field-effect mobilities (up to 15 cm2/V-s) for use in both n- and p-channel TFTs. Phase change materials, useful for rewritable optical media, have also been demonstrated, while thicker metal chalcogenide films have been solution deposited as solar cell absorber layers, yielding devices with up to 13% power conversion efficiency.

As an example, in the solar arena, only two metal-chalcogenide-based thin film photovoltaic technologies (cadmium telluride and Cu(In,Ga)(Se,S)2, also known as CIGS) had been able to offer power conversion efficiencies above 9%. We have recently shown world record performance - 9.6% efficiency - in a solution-processed kesterite-based device, in which the relatively rare and/or expensive In and Ga in CIGS have been replaced with plentiful relatively cheap Zn and Sn. Development of these and related high-performance solution-processed metal chalcogenide semiconductors offers outstanding opportunities for meeting price and performance targets in photovoltaics and microelectronics industries.

Biography:  Dr. David Mitzi received a B.S.E. in Electrical Engineering from Princeton University in 1985 and a Ph.D. in Applied Physics from Stanford University in 1990.  In 1990, he joined the I.B.M. J. Watson Research Center where he initiated a program examining crystal structure-property relationships and low-cost thin-film deposition techniques for a variety of electronic materials.

Currently, Mitzi manages the Photovoltaic Science and Technology group at IBM, with a focus on developing solution-processed high-performance inorganic semiconductors for thin-film PV devices.  Dr. Mitzi holds a number of patents and has authored or coauthored more than 140 papers and book chapters.