Synthesis of Hybrid Materials and Direct Patterning Inorganic Nanostructures via Infiltration Synthesis

Abstract:
Vapor-phase material infiltration in polymer templates is a relatively new material hybridization/synthesis and patterning technique derived from atomic layer deposition (ALD), where gaseous organometallic precursors infiltrate the polymer and react to form target inorganic material within the organic matrix. This enables not only the synthesis of novel inorganic-organic hybrids with enhanced physical properties but also a direct patterning of inorganic nanostructures directly converted from the starting polymer templates. In this talk, I will showcase our recent efforts on utilizing the method for patterning functioning metal oxide nanostructures based on self-assembled diblock copolymers (BCP) as well as lithographically-defined polymer structures. Various nanopatterns of metal oxides such as AlOx, ZnO, and TiOx could be generated with sub-30 nm feature sizes using BCP patterns, and three-dimensional metal oxide nanostructure with sub-40 nm linewidths and >15 aspect ratios by directly converting lithographically patterned polymer templates. The method also enabled a high-throughput wafer-scale fabrication of functioning in-plane ultrathin ZnO nanowire array field-effect transistors, featuring a unique fully-carrier-depleted state caused by oxygen chemisorption that has important implications in chemical and optical sensing applications. Finally, I will discuss the generation of metal-oxide-infiltrated polymer hybrids with enhanced material properties potentially applicable to, for example, hybrid polymer membranes with enhanced selective gas permeability, light hybrid materials with ultrahigh modulus of resilience (ability to store elastic energy), and stable organic-semiconductor-based photoanodes for photoelectrochemical water-splitting.

Biography:
Dr. Nam is a Scientist at the Center for Functional Nanomaterials of Brookhaven National Laboratory (BNL). He is also an Adjunct Professor at the Department of Materials Science and Engineering at Stony Brook University. Dr. Nam received his Ph.D. in Materials Science and Engineering at the University of Pennsylvania (2007) with the late John (Jack) E. Fischer, studying the synthesis and electrical & electromechanical properties of GaN nanowires for nanoelectronic device applications. Priorly, he received M.S. degree in Materials Science and Engineering from Korea Advanced Institute of Science and Technology (KAIST) (2001) and B.E. in Metallurgical Engineering form Korea University (2009). Dr. Nam joined BNL in 2007 as a Goldhaber Distinguished Fellow and was later promoted to a Scientist. During his near 10 year tenure at BNL, his research has been focused on: organic/hybrid photovoltaic and optoelectronic devices based on conjugated polymers & emerging semiconductors; application of self-assembled diblock copolymers for large-area patterning of functional inorganic nanostructures; and infiltration synthesis (atomic layer deposition) of semiconductor nanostructures & organic-inorganic hybrid materials for the functional applications in electronic devices, sensors, and energy technologies. His awards include Goldhaber Distinguished Fellowship (2007, BNL) and Spotlight Award (2011, BNL).