Papers by Keyword: Pulsed Laser Deposition

Abstract: High purity, micro, and nano size Ag₂O nanostructure films were deposited by pulsed laser deposition on the quartz substrates at different pulsed laser Energies. The Ag2O cubic structure is supported by structural and optical features, with the primary diffraction occurring from the (002) plane. The obtained band gap energy was around 2.25eV, and optical features indicate the temporal dependency of the energy gab.

Abstract: Polypyrrole (PPy), functionalized multi-walled carbon nanotube (f-MWCNT), nickel oxide (NiO) nanocomposites (NCs) films did prepare by PLD technique. The weight percentage of PPy/ f-MWCNT varied from 1 to 5 wt.% whereas NiO fixed with 8wt.%. The nanocomposite films were characteristics by XRD, Raman, FTIR, SEM, and EDS. The XRD pattern shows that the films of (NCs) indicating the amorphous structure of PPy and polycrystalline cubic crystal of NiO and hexagonal phase of f-MWCNT. The dominant phase for (NCs) represented by (002) for f-MWCNT, NCs were shifted to different values of 2θ. Raman spectroscopy the characteristics peaks of (G-D) band at (1280,1320,1570,1610) and the intensity increases with concentration increase to the NCs. FTIR spectra of (NCs) films, refer that C2 has a prominent absorption peak at 1292 cm^-1 and C4 at 1550 cm^-1 indicated the spectrum of PPy/NiO and from C1 at 2360 cm⁻¹ and C4 at 709 cm⁻¹ indicated the spectrum of PPy/CNT. The morphological studies revealed that tubular surface structure at (C1, C3, and C5) and cluster branching in (C2, C4). It shows agglomeration particles and porosity for the surface of the (NCs) films. For all measurements, the (NCs) succeeded in making the nanoparticles (f-MWCNT/NiO) held together in the polymer (PPy) matrix indicating, that a good interlinkage between PPy, f-MWCNT, and NiO. Keywords: PPy/f-MWCNT/NiO nanocomposites, pulsed laser deposition, Nd:YAG Laser.

Abstract: The work is devoted to the problem of thin metal coatings deposition on dielectric substrates using the method of target material pulsed laser evaporation. The main advantage of laser ablation over other methods of coating deposition is the possibility of using practically any material as a target, while the resulting films are characterized by a high correspondence of the phase and chemical composition to the target material. The possibility of using an electrostatic field to improve the efficiency of coating deposition process is considered. Under the action of an electric field formed between the plates of high-voltage electrodes, the ablation products leave the treatment area and settle on the substrate surface. Examples of coatings deposited under various ablation conditions are shown.

Abstract: Titanium is the most broadly employed implant material for the load bearing dental and the orthopedic uses due to its brilliant biological and mechanical characteristics. The aim of the present study is to assay the biological behavior of pure Titanium coated with a bioactive glass coating made by pulsed laser deposition. The coating characteristic and the biological behavior of coated specimens were assessed and compared with uncoated specimens. In vitro biological behavior including bioactivity, biocompatibility and antibacterial property was evaluated. The bioactivity of the specimens was assayed by immersion in a simulated body fluid for various times (7 and 14) days. Biocompatibility was assessed by MTT assay of L929 mouse fibroblast cells after 1, 3 and 5 days. Also, the antibacterial property was evaluated against S. aures by optical density method. The obtained results revealed that the pulsed laser deposited bioactive glass coating significantly improved the potential of Titanium for dental and orthopedic applications.

Abstract: The binary metal oxides of ZnO and MoO₃ (ZMO) nanostructured thin films were prepared by pulsed laser deposition at different temperatures such as 298(as deposited), 623, 773 and 923K at 10Hz laser repetition rates for 30 min. The films were characterized by XRD, UV-Visible spectroscopy and IV measurements. The XRD discloses the amorphous nature of the film deposited below 773K. Few peaks which were seen in 923K sample revealed the formation of ZnMoO₄ and Zn₃Mo₂O₉ for the binary ZMO thin films. The optical energy band-gap was measured using Tauc plot and was found to be 2.4 to 2.7eV. These films were investigated by electrochemical impedance spectroscopy over a frequency range of 1Hz–1MHz, for measuring temperatures lying in 298K-473K domain. The frequency response of the imaginary impedance (Z′′) shows relaxation behavior along every measuring temperature. The binary ZMO pulsed laser deposited at high temperatures demonstrates better semiconducting behavior. The activation energy (E_a) which is minimum for high temperature PLD thin films was determined from the Arrhenius plot based on impedance.

Abstract: In this work, the Nb₂O₅ nanostructure has been deposited using Q-switched Nd: YAG laser in the vacuum pressure of 0 bar pressure on quartz substrates. Physical properties of the prepared films at different substrate temperatures (300, 400, and 500) °C were characterized. The obtained results reflect the formation of good quality monoclinic Nb2O5 thin film. A clear blow shift was also obtained where the optical band gap increase from (to) with temperature. Finally, AFM results revealed the increase the surface roughness with substrate temperatures.

Abstract: In this study, pulsed laser deposition technique was used to deposit bismuth plumbum strontium calcium copper oxide {Bi (Pb)SrCaCu0} thin films on MgO single crystal substrate. Solid state procedure which is inexpensive technique used in the production process of the Bi (Pb)SrCaCu0 superconductor bulk sample. In this work, Handy YAG Lasers (model: HYL 101 E) has been used. It is a high power class 4 solid state (ND: YAG) Q-switched pulsed laser and 532 nm (visible green: second harmonic) has been used to ablate the films. The substrate used in this work was single crystal MgO with the (100) orientation. Scanning Electron Microscopy (SEM) was used to observe the microstructure of fracture surface and cross section of thin film materials. Variable Pressure Scanning Electron Microscope (LEO-VPSEM) was used to study the correlation between the microstructure features. SEM studies have shown that the surface morphology of the bulk sample comprises platelets of average size ≈10μm with uniform and homogenous microstructure. The typical morphology of the as deposited films showed a continuous phase, granular structure, which spherical particles up to 5μm in diameter. The most prominent types of particulates BPSCCO films on MgO substrate are droplets with smooth surface, bigger droplets with granular surface, spherically-shaped features confined by randomly oriented facets, submicron rod-like features, Cu-enriched needles, platelets, irregularly-shaped Cu-rich outgrowths, strongly Cu-enriched tabular outgrowths, big target fragments, island growth structure, cubic and rectangular cubic structures. SEM analysis also showed that the deposition time have a pronounced influence on the particle size. The target morphology, which develops under laser-irradiation, depends on the laser fluence and the technique, by which the laser beam is moved relatively to the target during ablation. Laser-irradiated surfaces normally become altered both physically and chemically and morphological changes take the form of periodic structures such as ripples and ridges.

Abstract: The paper discusses the findings of the study of the structural and magnetic properties of Zn_1-xMn_xO_y thin films (x = 0-0.08), synthesized by pulsed laser deposition under different conditions. It has been discovered that during the doping, thin films remain single-phased and retain wurtzite structure (ZnO _wurz), oriented along the direction (001). It has been determined that thin films obtained under the same synthesis conditions have similar crystallite sizes, which is confirmed by the substitution of Mn²⁺ ions with Zn²⁺ ions in the Zn O semiconductor matrix. It has been found that annealing of samples in the oxygen atmosphere increases the surface roughness from 1-3 nm to ~ 10 nm; the higher the concentration of manganese in Zn_1-xMn_xO_y films is, the greater the value of R_a. It has been demonstrated that, at room temperature, all Zn_1-xMn_xO_y thin films (x = 0-0.08) exhibit ferromagnetic behavior, which is more pronounced upon the increase in concentration of oxygen vacancies and manganese in the samples. It is assumed that two mechanisms explaining high-temperature ferromagnetism coexist in the films: the first one is determined by ferromagnetic exchange between Mn²⁺ cations by means of oxygen vacancies, the second one deals with super-exchange interaction between oxygen vacancies.

Abstract: Nd:YAG laser was used at different number of shots (300, 500, and 700 pulse) to prepare ZnO:Cu₂O nanoparticles at mixing ratios of (0.5, 0.7 and 0.9). The optical, structural, morphological and electrical properties of the prepared films were investigated. The energy band gap was found to be (2.5, 3.2 and 3.53 e.v). The crystalline structure showed no impurity peaks indicating that the final product was free from surface impurities. Also, the materials peaks and intensity is present and well identified as the mixing ratio varies. The AFM results for all ratios indicate that as the number of pulses increase, the higher the resulted grain size. The average grain size was between (58.82 nm) to (95.75nm). The J-V characteristics were measured for the prepared solar cells and it was found that the efficiency varied with the mixing ratio and film thickness from 0.29% to 2.38%. F.F varied from 0.28 to 0.25.

Abstract: The optical absorption spectrum, Photoluminesces, and non-linear optical properties for Copper Phthalocyanine (CuPc) thin films (150,300 and 450 nm) respectively have been investigated via pulsed laser deposition technique. The absorption spectrum indicted that there are two bands one in UV around 330 nm which called B-band and the second in Visible around 650nm which called Q-band. Photoluminescence spectrum related to deposit samples has been determined with different thicknesses. From closed and open aperture Z-scan data non-linear absorption coefficient and non-linear refractive index have been calculated respectively using He-Ne laser which have beam waist of (24.2 μm), wave-length of (632.8 nm) and Rayleigh thickness was 2.9 mm. Through dividing closed by open apertures, non-linear refractive index was calculated accurately. Finally, the study also showed the suitability of the deposited films as an optical limiter at the wavelength 632.8 nm.