Effects of static and dynamic femtosecond laser modifications of Ti/Zr multilayer thin films

The experimental study of the static and dynamic femtosecond laser ablation of the multilayer 15x(Ti/Zr)/Si system is reported. The layer-by-layer selective laser ablation mechanism was studied by analysis of the surface morphology and elemental composition in static single pulse irradiation in a range of pulse energy from 10 to 17 \upmu J. The selective ablations, as number of concentric circles in modified spots are increased with the pulse energy. The boundary between the circles was shown a change in the depth, comparable to the thickness of the individual layers. Changes in the elemental composition at the edges are associated with the removal of the layer by layer. The dynamic multipulse irradiation was observed via the production of lines with laser-induced periodic surface structures (LIPSS) at different laser parameters (scan velocities and laser polarization). The spatial periodicity of the formed LIPSS depends on changes in the effective number of pulses and laser polarization, as well as the nature of the material. For better interpretation of the experimental results, simulations have been conducted to explore the thermal response of the multiple layered structure 15x(Ti/Zr) after static single pulse irradiation

CROATIA. Risks and Opportunities Related to Media and Journalism Studies (2000–2020). Case Study on the National Research and Monitoring Capabilities.

Croatian media and communication studies have a long history dating from the 1960s in socialist Yugoslavia. The growth and advances of the field started strongly after 2000. The analysis of the Croatian corpus of published research between 2000 and 2020 has identified more than 400 literature sources useful for further research of the ROs domains of Journalism, Legal and ethical domain, Media usage domain, and Media-related competencies domain. The largest corpus is in the Journalism domain, testifying to the origins of the Croatian media and communication discipline, followed by the Legal and ethical domain. Audience research started to be seriously developed after 2011, and the research on Media-related competencies domain was almost nonexistent before 2011. While the number of publications in these two domains is smaller, a higher quality and international character of this research might offset its smaller number. The aim of this case study is to give an overview of published literature and other data sources in Croatia in the four domains that are seen as presenting risks or opportunities for deliberative communication: Legal and ethical domain, Journalism domain, Media usage domain, and Mediarelated competencies domain. The report is based on published studies (national and international) and reports, and provides information on data collections and research methodologies. The report also includes an analysis of research resources: expertise, financing and position of research and data collecting units, with the aim of assessing the quality of research, the institutionalization of the academic discipline(s) necessary for their study, and the resulting national research capabilities to monitor the four domains with respect to the relevant time frame of 2000–2020

CROATIA. Critical junctures in the media transformation process.

The present study details the critical junctures in the transformations of risks and opportunities in the four domains of media systems – the Legal and ethical environment, Journalism, Media usage, and Media-related competencies domain – that are expected to contribute to or deter from deliberative communication. Study includes a background chapter on social and political changes that influenced the four key domains Croatia. The study is based on the literature and other data sources identified in Case study 1 “Risks and Opportunities Related to Media and Journalism Studies (2000–2020). Case Study on National Research and Monitoring Capabilities”, but goes beyond it by offering an in-depth analyses of changes within each domain and identifying the actors behind them. Legal framework in Croatia is in most respects in accordance with European standards, but a degree of conflicting legislation exists regarding defamation offences. Frequent legislative changes (although most without a change of direction) show that a coherent policy-led system has not yet materialized. Evidence of hybridity of the media system is seen in media and related practices, which take place in a diverse yet highly concentrated media system, most similar to the Mediterranean polarized pluralist media system model from the Hallin and Mancini (2004) typology. Media-related competencies and media literacy appear to be higher in some areas and population groups than in others. Journalism market is diverse although subject to economic constrictions as well as pressures on journalists in the form of many SLAPP lawsuits

Laser irradiation of 10x(Ni/Ti)/Si multilayers at different wavelengths

A study of the effects of laser irradiation on the morphology and composition of Ni/Ti multilayers induced by nanosecond laser pulses at different wavelengths is reported. Irradiation of complex 109(Ni/Ti)/Si sample was done by a Nd:YAG laser which operate at a 1064 nm wavelength, frequency doubled wavelength (532 nm) and dual-wavelength (1064 and 532 nm). The following surface morphological changes were observed: (1) ablation of the thin film during the first laser pulse and (2) appearance of some nanostructures (mosaic structure) in the irradiated region. After action of one pulse, the boundary of damage area was relatively sharp at low pulse energy, whereas it was diffuse after irradiation with higher energy per pulse. The results obtained show that laser irradiation induced mixing between Ni and Ti layers which creates conditions for the formation of intermetallic compounds. A numerical model was used to predict ablation depths and temperatures inside the material during the time. The model prediction shows a close agreement with experimental data

High dose ion irradiation effects on immiscible AlN/TiN nano-scaled multilayers

The effects of high dose Ar ion irradiation on immiscible AlN/TiN multilayered structures were studied. The structures with 30 alternate layers of a total thickness of ~ 260 nm were deposited by reactive sputtering on (100) Si wafers. Individual layer thickness was ~ 8 nm AlN and ~ 9.3 nm TiN. Irradiation was done with 180 keV Ar ions to 1 × 10-8 × 10 ions/cm, with the projected range around mid-depth of the structures. It was found that the highest applied dose induced a considerable intermixing, where the growing TiN grains consume the adjacent AlN layers, transforming partly to (TiAl)N phase. Intermixing occurs due to a high contribution of collision cascades, which was not compensated in demixing by chemical driving forces. However, a multilayered structure with relatively flat surface and interfaces is still preserved, with measured nano-hardness value above the level for the as-deposited sample. The results are compared to other systems and discussed in the light of the existing ion beam mixing models. They can be interesting towards better understanding of the processes involved and to development of radiation tolerant coatings. © 2012 Elsevier B.V. All rights reserved

Morphology of WTi thin film processing by femtosecond laser

In this work we reported the effects of femtosecond laser on the morphology and structure of WTi thin film (thickness of ~190 nm) deposited on single crystal Si(100) wafer. Irradiation was performed in air by linearly polarized and focused femtosecond laser beam. The main characteristics of used laser system: pulse duration 40 fs, pulse repetition rate 1 kHz, wavelength 800 nm. The sample surface was irradiated using maximum energy of 7 μJ per pulse. The results demonstrate the possibility of laser induced periodical surface structures (LIPSS) formation on the thin film surface and on the Si substrate

Influence of Nitrogen Incorporation Sites on Structural and Optical Properties of Sputtered TiO2-N Thin Films with Improved Visible Light Activity

The influence of deposition and annealing parameters on optical, structural and photocatalytic properties of N-doped titanium-dioxide (TiO2) thin films have been studied. Anatase and anatase-rutile crystalline phase mixture TiO2 thin films were obtained depending on the reactive direct current (DC) sputtering and annealing conditions. Deposition in the nitrogen atmosphere produced N-doped TiO2 thin films with energy gap values shifted towards visible region in comparison with thin TiO2 films deposited without nitrogen in the atmosphere. The role of substitutional and interstitial nitrogen atoms incorporated in obtained crystalline structures during the deposition was shown important and was reflected in the efficiency of photocatalysis. It was found that thin TiO2 films with more substitutional incorporated nitrogen exhibits better photocatalytic properties. These results could be of importance towards achieving controlled synthesis of N-doped TiO2 thin films with desired structural and optical properties, especially with improved photo-activity in the visible part of the solar spectrum

Structure and surface composition of NiCr sputtered thin films

Thin films of nichrome were deposited by d.c. sputtering of a target (80%Ni 20%Cr w.t) by Ar+ions at a working pressure of 10-1 Pa and at room temperature. The phase composition and grain size were studied by X-ray Diffraction (XRD), while the surface chemical composition was determined by Low Energy Ion Scattering (LEIS). Analysis of phase composition showed that the NiCr thin films were a solid solution of chromium in a nickel matrix with increased nickel lattice parameters. LEIS analysis showed the presence of Ni Cr and O in the first atomic layer. There is a strong suspicion that surface passivation occurred by forming Cr2O3 oxide at the surface