= 아 래 =
1. 일 시 : 2014. 4. 30 (수), 16:00 ~
2. 장 소 : 신소재공학과 2429호 제 2세미나실
3. 연 사 : 김지환 박사(IBM T.J. Watson Research Center)
4. 제 목 : Atomic-precision Control of Two-dimensional Materials & Design Principles of Three-dimensional PV Architectures
Control of low-dimensional materials with an atomic/molecular level of precision is essential for realizing these materials for novel device applications. In today’s talk, I will present our current progress on layer-resolved manipulation of two-dimensional materials for future nanoelectronics and self-controlled nanopatterning techniques for three-dimensional (3D) photovoltaic applications. The fabrication of wafer-scale single-oriented graphene is one of the most important research goals in the field of graphene research. Graphene epitaxially grown on SiC has a single orientation, but its thickness cannot be limited to one layer. We have developed a technique for manipulating these graphene layers with a single-atom-thickness precision. This technique enabled us to exfoliate a one or two monolayer graphene grown on SiC and selectively remove the excess graphene, resulting in an unprecedented form of a flat, single-oriented, monolayer graphene in a 4-inch wafer-scale. In addition to accurate control of atomic layers, the precise control of atomic diffusion kinetics is also essential for current nanotechnology. We have developed a nanopatterning method to obtain sizetunable high-density arrays of Sn nanospheres by controlling oxidation/diffusion kinetics. Based on this nanopatterning method, we fabricated high efficiency 3D solar cells on high-aspect-ratio glass nanocones. Owing to the optimized nanocone morphology and optical components for a 3D architecture, we obtained an unprecedented efficiency of 9.4% from the 3D thin film Si solar cell.