Juergen Probst | Searcharxiv

arXiv2016

Correlated Diffuse X-ray Scattering from Periodically Nano-Structured Surfaces

Laterally periodic nanostructures were investigated with grazing incidence small angle X-ray scattering. To support an improved reconstruction of nanostructured surface geometries, we investigated the origin of the contributions to the diffuse scattering pattern which is correlated to the surface roughness. Resonant diffuse scattering leads to a palm-like structure of intensity sheets. Dynamic scattering generates the so-called Yoneda band caused by a resonant scatter enhancement at the critical angle of total reflection and higher-order Yoneda bands originating from a subsequent diffraction of the Yoneda enhanced scattering at the grating. Our explanations are supported by modelling using a solver for the time-harmonic Maxwell's equations based on the finite-element method.

cond-mat.mes-hall↗

arXiv2016

Deterministic aperiodic composite lattice-structured silicon thin films for photon management

Exotic manipulation of the flow of photons in nanoengineered semiconductor materials with an aperiodic distribution of nanostructures plays a key role in efficiency-enhanced and industrially viable broadband photonic technologies. Through a generic deterministic nanotechnological route, in addition to periodic, transversely quasicrystallographic or disordered random photonic lattices, here we show scalable nanostructured semiconductor thin films on large area nanoimprinted substrates up to 4cm^2 with advanced functional features of aperiodic composite nanophotonic lattices having tailorable supercell tiles. The richer Fourier spectra of the presented artificially nanostructured materials with well-defined lattice point morphologies are designed functionally akin to two-dimensional incommensurate intergrowth aperiodic lattices-comprising periodic photonic crystals and in-plane quasicrystals as subgroups. The composite photonic lattice-structured crystalline silicon thin films with tapered nanoholes or nanocone-nanoholes are presented showing up to +30 % achievable short circuit current density in comparison to a periodic counterpart where as it is up to +190 % in comparison to a reference unstructured silicon thin film of 300 nanometers of thickness. In view of scalable bottom-up integrated device fabrication processes, the structural analysis is further extended to liquid phase crystallized double-side-textured deterministic aperiodic lattice-structured 10 micrometers thick large area crystalline silicon film.

cond-mat.mes-hall↗