Ласерска модификација алуминијум-титанских и никл-титанских танких слојева
Laser modification of aluminium-titanium and nickel-titanium thin layers
AuthorSalatić, Branislav М.
Committee membersPetrović, Suzana
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Предмет истраживања ове дисертације су морфолошке и хемијске промене које настају на алуминијум-титанским и никл-титанским танким слојевима...
The main subject of this doctoral thesis is morphological and chemical changes that occurs on the aluminum-titan and nickel-titan thin films, after the treatment by nanosecond and picoseconds laser pulses. Aluminum-titan and nickel-titan multilayer systems are created by alternating deposition of nanometer layers (Al or Ni and Ti) on a single silicon substrate, by sputter deposition method. The samples were irradiated by Er:glass and Nd:YAG laser beam, at different intensities of laser radiation, with different number of pulses (1-20), at different wavelengths (1540 nm, 532 nm, 1064 nm and 1064/532 nm) and at different ambient conditions (air, water and ethanol). During the irradiation of target, most of the absorbed energy of the laser radiation is quickly transformed into heat, causing intensive morphological and chemical modification of the sample. The resulting changes depend on the characteristics of the laser radiation, material properties and ambient conditions. The study of las...er-induced changes is important for potential applications of these materials/systems in various fields of science and technology. Results of the laser modification of the multilayer systems, depending on the laser parameters, material properties and ambient conditions, have reflected an increasing surface roughness of the target, the formation of specific micro- and nanostructures, the occurrence of morphological characteristics as consequence of the movement of molten material and the creation craters caused by ablation of material. Laser modification of samples is accompanied by intensive surface melting of thin layers and possible mixing the components by thermally activated diffusion with indication of formation of intermetallic compounds (AlTi и NiTi). Laser-induced modification of aluminumtitanium and nickel-titanium thin films by two wavelengths simultaneously (1064/532 nm) is reflected in the intensive ablation of materials and formation of deeper and wider craters, compared to craters obtained at 1064 nm. The numerical model simulates effect of nanosecond laser pulses on the (Al /Ti)/Si and the (Ni/Ti)/Si multilayered systems, which is used to predict the depth of ablation and calculation of temperature profiles. Numerical and experimental results are well matched in the range of laser intensities used in the present experiment.