【报告时间】2016年6月7日上午10:00-11:00
【报告地点】玉泉校区曹光彪科技大楼231会议室
【报告题目】Nanointerface Engineering of Electronic and Phonon Transports in Nanostructured Semiconductors
【报告人】Pierre F.P. Poudeu
Ferdinand Poudeu is currently an Associate Professor of Materials Science and Engineering at the University of Michigan. He earned a Ph.D in Inorganic Solid State Chemistry (2004) from the Technical University of Dresden in Germany. He was a research associate at Northwestern University (2006 – 2007) and Michigan State University (2004 – 2006), and served as Assistant Professor of Chemistry and Materials Science at the University of New Orleans (2007 – 2011) where he was named Early Research Professor (2010-2011) in recognition of his “outstanding and innovative work”. He joined the Materials Science and Engineering at the University of Michigan as Assistant Professor in 2011, where he established the Laboratory for Emerging Energy and Electronic Materials. His research portfolio currently includes (1) bulk nanostructured thermoelectric materials; (2) novel low-dimensional spintronic materials; (3) multifunctional quantum metamaterials; and (4) intercalation compounds for lithium rechargeable batteries. Dr. Poudeu has published over 70 journal articles in Science, JACS and other journals.
【报告摘要】
Electronic properties in semiconductors traditionally can be manipulated through alteration of the carrier density using (1) chemical doping, substitution and/or physical means. Unfortunately, these strategies adversely affect the thermopower (S) and electrical conductivity (σ) making it difficult to achieve simultaneous improvements in both properties. Our recent work on nanostructured half-Heusler (HH) alloys demonstrated that the thermoelectric properties of HH matrix with a given composition could be significantly improved through coherent atomic-scale integration of suitable nanoinclusions. It is believed that the coherent nanoinclusions effectively decoupled charge carriers with respect to their energy at the matrix/inclusion interfaces by trapping low-energy carriers while promoting the transport of high-energy carriers across the interfaces. This results in a large decrease in the effective charge carrier density along with an increase in the carrier mobility leading the large enhancements on both S and σ of the bulk nanostructured materials. In this talk, I will discuss using X-ray powder diffraction, electron microscopy and electronic transports data, the mechanism of nanometer scale phase formation in bulk HH matrix and the mechanism by which the embedded nanostructures regulate electronic charge transport within HH matrices with various doping levels.
