ChBE Seminar Series: Greg Guoliang Liu
Tuesday, March 4, 2014
11:00 a.m.-12:00 p.m.
Room 2108, Chemical and Nuclear Engineering Building
Professor Ray Adomaitis
Nanolithography Using Block Copolymers
Greg Guoliang Liu
Department of Chemistry and International Institute for Nanotechnology
Block copolymers are versatile materials that have rich chemical and physical properties. Here I present the utilization of these materials to address challenges in two distinct fields. 1) In microelectronics, the size and density of patterned features determine the power of a device. The 2018 target for a microprocessor unit is 15.0 nm half-pitch, which is a daunting challenge in the semiconductor industry. My graduate research focused on addressing this challenge by integrating directed assembly techniques with conventional lithography, where block copolymers were used to form densely-packed features as small as 13.5 nm. 2) In nanoparticle chemistry, it is challenging to synthesize patterned nanoparticles on a surface with control over size, shape, and composition. By integrating block copolymers with scanning probe lithography, my postdoctoral work demonstrates that single nanoparticles can be synthesized by precisely controlling the amount of metal precursors (Au, Ag, Pt, Pd, Fe, Co, Ni, or Cu) in each patterned polymer nanoreactor. The block copolymer significantly enhances the mobility of metal precursors, thereby mediating diffusion and coalescence of precursors to form single nanoparticles. This capability opens up the possibility of creating combinatorial nanoparticle libraries for catalyst screening. In addition, it creates an opportunity for studying the energetics associated with single particle formation from atomic precursors.
About the Speaker
Greg Guoliang Liu received his B. S. in Chemical Engineering from Zhejiang University, P. R. China in 2005, and his Ph.D. degree in Chemical Engineering from the University of Wisconsin-Madison under the supervision of Prof. Paul F. Nealey in 2011. Before completing his Ph.D. degree, his research in block copolymer lithography was recognized by Hitachi GST (San Jose, California), and he was recruited to apply his findings in magnetic data storage in 2010. Currently, he is an International Institute for Nanotechnology Outstanding Postdoctoral Fellow at Northwestern University under the direction of Prof. Chad A. Mirkin.