Numerical methods for characterisation of micro- and nanostructures
Final Report Abstract
Submicron structures (less than 1µm in size), and nanostructures in particular (1nm - 100nm in size) have increasingly become a focus of modern technological development. When nanoparticles are contaminants, information on their shape and material composition can help identify the source of contamination. The principal aim of this project was to develop an optical method for fast and accurate characterization of nanostructures on surfaces. In collaboration with Danish Fundamental Metrology who conducted the measurement of the nanostructures investigated. Using Optical Diffraction Microscopy we demonstrated that using inverse theory the profile of a Pt submicron wire on a rough Si substrate can be estimated with a relative errors of approx. 8%. An efficient forward scattering model was implemented for conductive and dielectric two dimensional nanoparticles on lossy substrates. The model is based on the Discrete Sources Method and it was investigated regarding accuracy, convergence and speed of computation. Based on this an inverse scattering method was implemented and tested for accuracy and efficiency. The method incorporated the Discrete Sources Method forward model, and it was applied to PEC and highly conductive penetrable nanowires on silicon substrate.
Publications
- “A fast inversion method for highly conductive submicron wires on a substrate,” Journal of the European Optical Society – Rapid Publications 6(11039), 2011
M. Karamehmedović, P.-E. Hansen, T. Wriedt
- “An efficient scattering model for PEC and penetrable nanowires on a dielectric substrate,” Journal of the European Optical Society – Rapid Publications 6(11021), 2011
M. Karamehmedović, P.-E. Hansen, T. Wriedt
- “Comparison of numerical methods in near-field computation for metallic nanoparticles,” Optics Express 19(9), 2011
M. Karamehmedović, R. Schuh, V. Schmidt, T. Wriedt, C. Matyssek, W. Hergert, A. Stalmashonak, G. Seifert, O. Stranik
- “Profile estimation for Pt submicron wire on rough Si substrate from experimental data,” Optics Express 20(19), 2012
M. Karamehmedović, P.-E. Hansen, K. Dirscherl, E. Karamehmedović, T. Wriedt
(See online at https://doi.org/10.1364/OE.20.021678) - “An efficient rough-interface scattering model for embedded nano-structures,” Thin Solid Films 541, 2013
M. Karamehmedović, P.-E. Hansen, T. Wriedt
- “Numerical simulation of Electron Energy Loss Spectroscopy using a Generalized Multipole Technique,” Ultramicroscopy 133, 2013
L. Kiewidt, M. Karamehmedović, C. Matyssek, W. Hergert, L. Mädler, T. Wriedt
(See online at https://doi.org/10.1016/j.ultramic.2013.07.001)
