Author, Institution: Aušrinė Jurkevičiūtė, Kaunas University of Technology
Science area, field of science: Technological sciences, Materials Engineering, T008
Scientific Supervisor: Prof. dr. Tomas Tamulevičius (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008)
Dissertation Defence Board of Materials Engineering Science Field:
Prof. habil. dr. Arvaidas Galdikas (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008) – chairman;
Dr. Viktoras Grigaliūnas (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008);
Dr. Till Leissner (University of Southern Denmark, Natural Sciences, Physics, N002);
Dr. Ieva Plikusienė (Vilnius University, Natural Sciences, Chemistry, N003);
Dr. Juris Prikulis (University of Latvia, Technological Sciences, Materials Engineering, T008).
The doctoral dissertation is available at the library of Kaunas University of Technology (K. Donelaičio St. 20, 44239 Kaunas, Lithuania).
Metallic nanoparticles exhibiting plasmonic properties are attractive for applications in optical sensors. The optical response of nanoparticles depends on their shapes and sizes as well as on surrounding medium. In order to prevent unwanted environmental effects for nanoparticles and to maintain the desired properties of plasmonic metals, nanoparticles can be embedded in a matrix of another material. Additionally, optical properties can be altered by imposing periodic lines in the material.
In this dissertation, a systematic study of copper (Cu) and silver (Ag) nanoparticles in diamond-like carbon (DLC) matrix is provided. Nanocomposites with varying metal concentration were deposited by reactive unbalanced magnetron sputtering technique. DLC:Cu and DLC:Ag dispersion curves, obtained from spectroscopic ellipsometry, have features associated with plasmonic properties. Two-photon luminescence images show that these properties are maintained for a long period of time, thus, DLC has effectively protected metal from the environmental effects.
One-dimensional periodic structures in DLC:Ag were imposed by direct laser interference patterning method. Initial bimodal distribution of nanoparticle diameters was successfully changed into unimodal distribution. Patterning of nanocomposites is possible when laser fluence is at or above patterning threshold. In order to pattern DLC:Ag nanocomposite, the needed energy density is 4-24 times smaller compared to DLC and Ag patterning thresholds.