Events Calendar

Distinguished Lecture Series

Speaker: Professor Thomas O. Mason, Northwestern University, Department of Materials Science & Engineering

Talk Title: High Performance Oxide Conductors and Semiconductors

Series: Distinguished Lectures Series

Abstract: Highly conductive ceramics (e.g., superconductors, semi-metallic oxides, ionic conductors) are well known, as are highly resistive ceramics (e.g., dielectrics, insulators, ferroelectrics). Since the advent of oxide-based chemical sensors (e.g., SnO2-based) and voltage-dependent resistors or “varistors” (e.g., ZnO-based) circa 1970, there has been a steady rise of interest in oxide semiconductors. The renaissance of oxide semiconductors over the past two decades has been particularly dramatic. For example, publications dealing with ZnO have doubled each half-decade since 1990 to more than 25,000 papers (2006-2010). This talk will focus on “medium band gap” (~3 eV) post-transition metal oxides, the basis set of which include CdO, ZnO, In2O3, and SnO2. (Ga2O3 is also of interest, although its band gap is significantly larger.) These compounds and their numerous binary, ternary and multinary compounds and solid solutions are known for their rare combination of high electronic conductivity (when degenerately doped) and optical transparency, and are collectively referred to as transparent conducting oxides or TCOs. TCOs find application as transparent electrodes in display technologies and photovoltaics. When non-degenerately doped, many of the same compounds/solid solutions can serve as thermoelectric oxides or TEOs for direct conversion of heat (solar, commercial, vehicular) to electricity. When very lightly doped, these same materials are excellent “transparent oxide semiconductor” (TOS) candidates for channel materials in oxide-based transparent thin film transistors (TTFTs), especially in the amorphous state (so-called “amorphous oxide semiconductors”). These can be deposited at low temperatures on flexible (polymer) substrates, thereby enabling oxide-based “transparent” and “flexible electronics.” This talk “dusts off” two long-standing (but under-utilized) semiconductor analysis procedures—so-called “Jonker” and “Ioffe” analyses—and applies them to the characterization/optimization of high-performance oxides for advanced applications in display, information technology, and energy conversion technologies.

Host: Professor Thompson

More Info: http://chems.usc.edu/academics/10-11/d-01-27-11.htm

Location: James H. Zumberge Hall Of Science (ZHS) - 159

Audiences: Everyone Is Invited

Contact: Petra Pearce

Event Link: http://chems.usc.edu/academics/10-11/d-01-27-11.htm