Lecture of "Semiconducting and Metallic Nanomaterials and Nanostructures: From Optical Properties to Biosensing"

Lecture of "Semiconducting and Metallic Nanomaterials and Nanostructures: From Optical Properties to Biosensing"

 TOPIC:

Semiconducting and Metallic Nanomaterials and Nanostructures: From Optical Properties to Biosensing

 LECTURER:

Dr. Qihua Xiong 熊启华博士

Assistant Professor of Nanyang Technological University, Singapore

11:00am, 7 July 2011 (Thursday)

 LOCATION:

 ABSTRACT:

Rational synthesis and fabrication of high quality, large scale semiconducting and metallic nanomaterials and nanostructures are of fundamental importance towards functional nanoscale optoelectronic and nanophotonic devices. In this presentation, we will discuss our recent progress in large scale vertically aligned synthesis of semiconducting nanowire arrays with catalyst-free growth via a novel van der Waals epitaxy mechanism. A selection of binary semiconductor nanowires (ZnO, ZnS, ZnTe, CdS, CdSe, CdTe and PbS) were synthesized on (001) muscovite mica substrate using a vapor transport process without any introduction of foreign catalyst. Optical characterizations indicate that those wires are of high quality, which enables the observation of 1st order exciton emission along with its phonon replica. Similar strategy can also result in polytypic tripod nano- and microcrystals of II-VI semiconductor on muscovite mica with pronounced preferential orientation of the tripods' legs with respect to the substrate, which is a strong indication of epitaxial relation. In addition, we will also present a flexible artificial metallic periodic nanostructures, i.e., split-ring resonator based flexible metamaterial (Metaflex) photonic device operating in Vis-IR regime, fabricated by state-of-the-art nanofabrication with the least width of 25 nm, which shows potential applications in high sensitivity strain, biological and chemical sensing. Lastly, the coupling between semiconducting nanomaterials and plasmonics nanostructures will be discussed.

 LECTURER BIO:

Dr. Qihua Xiong is currently an assistant professor working in Nanyang Technological University, holding both a Nanyang Assistant Professorship position of NTU and a Fellow of Singapore National Research Foundation. He finished his B.S. degree in Physics at Wuhan University in 1997, and a M.S. degree in physics from Shanghai Institute of Applied Physics, CAS in 2000. In 2006, he received his Ph.D. degree in materials science at The Pennsylvania State University under the supervision of Professor Peter Eklund. Prior to joining NTU, he spent three years working as a postdoctoral fellow in Harvard University with Professor Charles Lieber.

His research spans a wide range of topics broadly defined in nanoscience and nanotechnology, particularly in four areas. (1) novel optical properties concerning electrons, phonon and photons in nanowires due to strong confinement and anisotropy in 1D systems studied by absorption and Raman spectroscopy, photoconductivity and photoluminescence; (2) Unique high mobility and high performance nanoelectronic devices based on one-dimensional electron gas in nanowire heterostructures; (3) Nano-bio interfaces based on nanopore biosensing and plasmon biosensing and (4) Coupling between semiconductor nanomaterials and metallic nanostructures to investigate the energy transfer between plasmon and excitons. He has published over 30 papers including 4 review articles with a total citation of more than 750. He has four patent and patent applications, two of which on nanopore sequencing have been licensed to a UK-based company.