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Title: Molecular pathways for defect annihilation in directed self-assembly.

Over the last few years, the directed self-assembly of block copolymers by surface patterns has transitioned from academic curiosity to viable contender for commercial fabrication of next-generation nanocircuits by lithography. Recently, it has become apparent that kinetics, and not only thermodynamics, plays a key role for the ability of a polymeric material to self-assemble into a perfect, defect-free ordered state. Perfection, in this context, implies not more than one defect, with characteristic dimensions on the order of 5 nm, over a sample area as large as 100 cm2. In this work, we identify the key pathways and the corresponding free-energy barriers for eliminating defects, and we demonstrate that an extraordinarily large thermodynamic driving force is not necessarily sufficient for their removal. By adopting a concerted computational and experimental approach, we explain the molecular origins of these barriers, how they depend on material characteristics, and we propose strategies designed to over-come them. The validity of our conclusions for industrially-relevant patterning processes is established by relying on instruments and assembly lines that are only available at state-of-the-art fabrication facilities and, through this confluence of fundamental and applied research, we are able to discern the evolution of morphology at the smallest relevant lengthmore » scales - a handful of nanometers -, and present a view of defect annihilation in directed self-assembly at an unprecedented level of detail.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [4] ;  [6] ;  [7] ;  [3] ;  [3]
  1. Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Chicago, IL (United States); Chonnam National Univ., Gwangju (Korea)
  2. Cornell Univ., Ithaca, NY (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Chicago, IL (United States)
  4. Univ. of Chicago, IL (United States)
  5. Argonne National Lab. (ANL), Argonne, IL (United States)
  6. Georg-August Univ., Gottingen (Germany); Fudan Univ., Shanghai (China)
  7. Georg-August Univ., Gottingen (Germany)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal ID: ISSN 0027-8424
National Academy of Sciences, Washington, DC (United States)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
77 NANOSCIENCE AND NANOTECHNOLOGY; block copolymer; defect; kinetics; minimum free-energy path; string method
OSTI Identifier: