High-Density Nanowells Formation in Ultrafast Laser-Irradiated Thin Film Metallic Glass

Abstract

We present an effective approach for fabricating nanowell arrays in a one-step laser process with promising applications for the storage and detection of chemical or biological elements. Biocompatible thin films of metallic glasses are manufactured with a selected composition of Zr65Cu35, known to exhibit remarkable mechanical properties and glass forming ability. Dense nanowell arrays spontaneously form in the ultrafast laser irradiation spot with dimensions down to 20 nm. The flared shape observed by transmission electron microscopy is ideal to ensure chemical or biological material immobilization into the nanowells. This also indicates that the localization of the cavitation-induced nanopores can be tuned by the density and size of the initial nanometric interstice from the columnar structure of films deposited by magnetron sputtering. In addition to the topographic functionalization, the laser-irradiated amorphous material exhibits structural changes analyzed by spectroscopic techniques at the nanoscale such as energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy. Results reveal structural changes consisting of nanocrystals of monoclinic zirconia that grow within the amorphous matrix. The mechanism is driven by local oxidation process catalyzed by extreme temperature and pressure conditions estimated by an atomistic simulation of the laser-induced nanowell formation.

Dual-functionalized titanium by ultrafast laser texturing to enhance human gingival fibroblasts adhesion and minimize Porphyromonas gingivalis colonization

“…To complete the characterization of the impact of LIPSS on cell adhesion, it would be interesting in the future to study the surface chemistry of Ti6Al4V samples to identify oxides known to form during fs-L texturing [31]. To this end, a combination of FIB-STEM [32], TOF-SIMS [33], RAMAN and XPS may be pursued to evaluate the oxide layer thickness, oxides composition and the adsorption at the oxidized surface. Nevertheless, the increased wettability is of interest for the adhesion of fibroblasts, as cells that properly adhere to a surface cover a wider area (by spreading or migration) and typically with considerable strength.…”

Chemical and Topographical Changes upon Sub‐100‐nm Laser‐Induced Periodic Surface Structure Formation on Titanium Alloy: The Influence of Laser Pulse Repetition Rate and Number of Over‐Scans

“…In such a non-ablative processing regime, the reduced mass density imposes an increased specific volume of the nearsurface material manifesting as a surface protrusion then. [30] Additionally, sub-surface nanovoids may form upon ultrashort pulsed laser-induced irradiation of metals, [33] an effect that may also contribute to the surface swelling here. In summary, generally a good agreement between SEM and AFM spatial periods is found.…”

Dynamics of Cu–Zr metallic glass devitrification under ultrafast laser excitation revealed by atomistic modeling

“…Furthermore, the devitrification of CuZr MG using X-ray was confirmed experimentally, but no mechanism was proposed for such a process [60]. In laser processing, ultrafast laser irradiation can be used to induce the amorphous-crystal transformation [61]. However, the mechanism and thermodynamic conditions behind this transformation remain largely unknown [62][63][64][65][66][67][68][69][70][71].…”