Petr Novák

University of West Bohemia · New Technologies - Research Centre

Understanding of how the defects interact with each other and affect the properties of ZnO:Al thin films is one of great importance for improving their performance as a transparent conductive oxide. In the present work we studied the effect of annealing on the carrier concentration and Hall mobility of under-stoichiometric ZnO:Al films. Samples hav...

Grain boundary scattering reduces the mobility of free carriers in polycrystalline transparent conductive oxides. This is particularly significant in a sputtered low-thickness Al doped ZnO (AZO) films prepared at low deposition temperatures as the films often exhibit columnar structure and the density of boundaries influences its electrical propert...

In this study, Titanium (Ti) doped zinc oxide (ZnO) thin films were successfully deposited by reactive magnetron co-sputtering in a reactive mode from metallic targets with different Ti concentrations (up to 9 at % of Ti) at relatively low temperatures (~ 200 °C) to investigate changes of the microstructure. Detailed crystal and local atomic struct...

Reactive high-power impulse magnetron sputtering was used for high-rate (deposition rate of 60 nm/min) deposition of conductive (resistivity of 3 × 10 ⁻³ Ωcm) and optically transparent (extinction coefficient at the wavelength of 550 nm of 0.01) ZnO:Al thin films at ambient temperature (< 40 °C). We used planar Zn:Al target (3.09 at.% of Al) with d...

Aluminum-doped zinc oxide (AZO) is a suitable material for use as transparent electrode. Due to its lower price it is applied in the production of silicon solar cells. However, it is difficult to obtain suitable electrical properties at low deposition temperatures. Moreover, the AZO films with low thickness exhibit significantly higher average resi...

This work presents a detailed study of aluminium-doped zinc oxide thin films sputtered at 100 °C, with a focus on the correlation between structural and electrical properties. The structural properties are identified by SEM microscopy and X-ray diffraction, while the electrical properties are described by means of the carrier concentration and the...

Barium titanate (BaTiO3, BTO) is a perovskite class material of remarkable dielectric, ferroelectric and ferromagnetic properties. Our previous studies on optical properties of BTO thin films proved high visible transmittance and sharp absorption edge at ∼300 nm. Therefore the usage of BTO as a UV blocker or an antireflection (AR) coating in visibl...

In the present work co-sputtering from ceramic and metallic targets is used to reduce the oxygen content in aluminium doped zinc oxide. Films with thickness between 200 and 220 nm are sputtered at 100 and 250 °C and investigated by X-ray diffraction, energy dispersive spectroscopy, and Hall measurements. It is found that reducing of the incorporate...

In this paper we report results from optical transmittance spectroscopy complemented with data on structure from XRD measurements to determine optical properties of a series of ZnTiO3 perovskite thin films deposited on glass by reactive magnetron co-sputtering. The members of the series differ by the titanium content that was revealed as an origin...

The fabrication of inorganic transparent conductive oxide films on polymer substrates has been of increasing interest due to their potential applications in the field of flexible electronics. The subject of the present work is replacing the preferably-used indium tin oxide films by an aluminium zinc oxide (AZO) film in ZnO-nanorod-based devices, co...

Structural and Electronic Properties of Ti Doped ZnO: XRD, TEM, EELS and Ab-initio Simulations - Volume 23 Issue S1 - Medlin Rostislav, Minar Jan, Sutta Pavol, Khan Wilayat, Sipr Ondrej, Novak Petr, Netrvalova Marie

Zn-Ti-O thin films with different concentrations of titanium were deposited by reactive magnetron co-sputtering in a reactive Ar/O2 atmosphere from zinc and titanium targets. It was found that with increasing Ti content the structure of the films gradually changes from a fully crystalline pure ZnO wurtzite structure with a strongly preferred column...

ZnO is a wide used ferroelectric material with a variety of applications. This study investigates ZnO thin films doped by Ti as showing structure change from ZnO wurtzite up to ZnTiO 3 perovskite. ZnO:Ti thin films were prepared by RF reactive magnetron co‐sputtering in Ar/O 2 atmosphere from pure Zinc and Titanium targets (99.99%). Changes of amou...

This study demonstrates that a laser-induced crystallization instrumented with Raman spectroscopy is, in general, an effective tool to study the thermally activated crystallization kinetics. It is shown, for the solid phase crystallization of an amorphous silicon thin film, that the integral intensity of Raman spectra corresponding to the crystalli...

In this article, we report the fabrication of transition metal (TM = Co/Ni) and Nb co-doped SrTiO3 (Ni0.06Nb0.05Sr0.12Ti0.16O0.61 and Co0.08Nb0.05Sr0.11Ti0.15O0.61) thin films of thickness around 1.1 μm on monocrystalline Si (100) substrate by RF sputtering at 350 °C. The as-deposited amorphous films were annealed at 800 °C in vacuum to obtain crys...

Thin films of BaTiO3 and Co, Nb co-doped BaTiO3 on glass and Si (100) substrates were deposited by RF sputtering (at 350 ºC), and annealed. The amorphous and crystalline phases were observed for the as-deposited and annealed samples, respectively from the X-ray diffraction (XRD) studies. The magnetic behaviour of the pure and doped BaTiO3 films was...

The effect of annealing on structural and magnetic properties of the RF sputtered BaTiO3 and Co, Nb co-doped BaTiO3 thin films on Si (001) substrates were studied. The structure of the as-deposited (amorphous) films was changed into cubic perovskite phase during the in-situ X-ray diffraction from room temperature to 900°C. The enhancement of crysta...

Abstract Nickel doped ZnO (ZnO:Ni) thin films are considered to be promising materials for optoelectronic applications. The doping of transition metal ion modifies the optical and physical properties of the materials. Therefore, studies on optical and physical properties are important for such applications. In the present work, the ZnO:Ni thin film...

Abstract In the present work we investigate thin amorphous silicon film fabricated by plasma enhanced chemical vapor deposition. In particular, we analyze changes in the recorded Raman spectra caused by excitation laser irradiation. Solid phase crystallization, hydrogen diffusive outflow and Raman spectra peak shifts have been observed experimental...

Zinc Oxide (ZnO) is a wide bandgap semiconductor material which can be successfully used for wide variety of applications such as biosensors and acoustic resonator devices. ZnO normally crystallizes in the wurtzite structure with c-axis (002) preferred orientation. However, for bio-sensing in liquids, it is necessary to generate a shear horizontal...

Abstract Nickel doped zinc oxide (ZnO:Ni) thin films with different Ni concentrations were deposited on silicon substrates at 400 °C by reactive magnetron sputtering using a mixture of Ar and O2 gases. The X-ray diffraction and azimuthal patterns of the ZnO:Ni were carried out, and the quality of the strong preferred orientation of crystalline colu...

Zinc Oxide (ZnO) is a wide bandgap semiconductor material which can be successfully used for wide variety of potential applications such as biosensors or acoustic resonator devices. ZnO normally crystallizes in the wurtzite structure with c-axis (001) preferred orientation. However, for bio-sensing in liquids, it is necessary to generate a shear ho...

The Johnson–Mehl–Avrami–Kolmogorov (JMAK) model is widely used to quantify the isothermal crystallization kinetics. The present work reports an analytical solution for the crystallization kinetics in the special case of plate-shaped samples with a finite thickness. As a result, we obtained an adapted JMAK model revealing the thickness range which i...

The article reports on mechanical and tribological properties of Mo–O–N coatings prepared by reactive magnetron sputtering using a continuous and pulsed inlet of oxygen and nitrogen. Main attention was devoted to a detailed investigation of correlations between the coating structure and its mechanical and tribological properties. The structure of c...

The effects of deposition conditions (especially lateral position against target during deposition and deposition temperature) on optical properties and structure are presented. The X-ray diffraction (XRD) analysis showed that all the films were polycrystalline with hexagonal structure and preferred orientation in [001] direction perpendicular to t...

The article reports on the dependency of friction and wear of a-(Ti,C,N) films on the nitrogen content. The amount of nitrogen N in the film was controlled by partial pressure of nitrogen pN2 in the Ar+N2 sputtering gas mixture. It is shown that the incorporation of N in the film results in the increase of (i) the coefficient of friction μ (increas...

The paper reports on preparation of ~3000nm thick a-C coatings containing Mo, interrelationships between their mechanical properties, a coefficient of friction μ and wear rate k and the effect of Mo content in the a-C coating on these interrelationships. The Mo–C coatings were prepared by sputtering using an unbalanced magnetron (UM) equipped with...

This article reports on interrelationships between x-ray structure, mechanical properties, coefficient of friction μ, and wear coefficient k of ∼3000 m thick nc-TiC/a-C nanocomposite films sputtered using unbalanced magnetron from a composed C/Ti target (=100 mm); here nc and a denotes the nanocrystalline and amorphous phase, respectively. It is s...