title: Nanoscale characterization of local structures and defects in photonic crystals using synchrotron-based transmission soft X-ray microscopy.
abstract: For the structural characterization of the polystyrene (PS)-based photonic crystals (PCs), fast and direct imaging capabilities of full field transmission X-ray microscopy (TXM) were demonstrated at soft X-ray energy. PS-based PCs were prepared on an O2-plasma treated Si3N4 window and their local structures and defects were investigated using this label-free TXM technique with an image acquisition speed of ~10 sec/frame and marginal radiation damage. Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components. Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated. This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea.
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Nho
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea.
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Kalegowda
authors.affiliation: Pohang Accelerator Laboratory and Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
authors.forename: Hyun-Joon
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea.
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Yoon