The experimental study of the dynamic femtosecond laser substrate pre-patterning of the Ti/Zr/Ti thin film system is reported. The design of surface pattering with the micrometer features in the form of spikes is investigated in order to improve the arrayed surface structures for biomedical applications. Femtosecond laser pulses were used to acquire black silicon surfaces decorated with conical structures (spikes) on crystalline silicon surfaces under 6.5×102 mbar of SF6 environmental atmosphere. After irradiation, the silicon surface exhibits high aspect ratio spikes, which have conical shapes of about 2 μm height, 40° angle opening, 13×106 cm−2 density that remains approximately uniform across the processed area. Results show that the base of the induced conical structures has an elliptical shape with a major (long) and minor (short) axis on the horizontal plane. It is revealed that the orientation of the long axis of the ellipsis is polarization-dependent with the long axis oriented always perpendicularly to the electric field of the laser beam. Spike formation has been attributed to a complex mechanism initiated by partial material melting and subsequent capillary wave formation driven by surface tension gradients within the molten region. Ion sputtering was used to create unique composite thin films on pre-patterned Si substrates that consist of two layers of Ti and subsurface layer of Zr on the interface of titanium. The total thickness of the deposited composite in Ti/Zr/Ti form was 300 nm. The composition, surface morphology and wetting properties were analyzed by scanning electron microscopy (SEM-EDS), profilometry and wettability measurements. The formation of micro-patterns with spikes array of composite Ti/Zr/Ti thin film systems was used to observe the effects of morphology on survival, adhesion and proliferation of the MRC-5 cell culture line. To determine whether Ti/Zr/Ti thin films have a toxic effect on living cells, an MTT assay was performed. The relative cytotoxic effect as a percentage of surviving cells showed that there was no difference in cell number between the Ti/Zr/Ti thin films and the control cells. There was also no difference in the viability of the MRC-5 cells.IX International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; August 28 - September 1, 2023; Belgrad
