Abstract:

The conventional electronic system has been developed upon Si-based thin-films because of their cost-effectiveness and mature process. However, there are fundamental limitations in using conventional systems towards future electronics such as wearable devices, biomedical devices, and edge computing devices. One of these most prevalent limitations is that current thin-film electronic systems have been developed on rigid wafers, which causes serious physical constrains because of the thick nature of the materials on the rigid wafers. Thus, an alternative approach has been required to secure mechanically low stiffness of materials and devices.

In this talk, I will discuss about our recent effort to tackle the aforementioned challenge by developing 3D and 2D freestanding nanomembranes. First of all, we have conceived an approach to obtain freestanding single crystalline materials through 2D materials assisted layer-transfer (2DLT). While developing it, we found out that crystallographic information can penetrate through graphene as long as substrates have polarity because of graphene’s information transparency. Also, the slippery nature of graphene enables spontaneous relaxation, which substantially reduces dislocation density in heteroepitaxy. Second, we have developed mechanics to produce 2D materials by playing interfacial toughness contrast. As this approach allows producing various 2D materials at large-scale, various applications can be demonstrated at practical level. Also, we realized that geometrical confinement helps kinetic control of 2D materials, which secures crystallinity, layer-controllability, and heterostructures. As the 3D and 2D freestanding membranes are a new type of building blocks, various opportunities are expected by providing a new platform where physical couplings and practical applications are conceived.

Bio:

Sang-Hoon Bae is an Assistant Professor in Washington University in St. Louis. He was a postdoctoral research associate at Massachusetts Institute of Technology (MIT) working with Professor Jeehwan Kim before joining Washington University. He earned a doctorate in materials science and engineering from University of California, Los Angeles (UCLA) under the supervision of Professor Yang Yang in 2017. He earned bachelor's and master's degrees in materials science and engineering from Sungkyunkwan University (SKKU), Korea, under the supervision of Professor Jong-Hyun Ahn in 2013. He worked at IBM T. J. Watson Research Center (2014) and Samsung Display (2010) as a research intern. He has published more than 70 papers in notable journals including Science, Nature, PNAS, Nature Materials, Nature Nanotechnology, Nature Photonics, and Nature Electronics with over 8000 citations. His h-index is 41 as of March 2023.