PbO Target Research Articles

New mechanistic insight on the synthesis of metal carbonates by laser ablation in ethanol

We present new results concerning the formation mechanism of lead carbonate (Pb3(CO3)2(OH)2) by laser ablation in ethanol, under controlled atmospheres. We suggest that carbon dioxide (CO2) is absorbed from ambient atmosphere and converted into carbonate in a reaction mediated by ethoxide anion produced during the ablation. Addition of 2,4,6 trinitrotoluene to the ablated solution and its subsequent reduction, followed by UV–Vis spectroscopy, supports this new mechanism. No carbonate precipitates under Ar or O2 atmospheres. Ablation of Pb, PbO, Bi or Bi2O3 targets in ethanol were also carried out. The precipitated powder samples were analyzed by XRD, FTIR, Raman, SEM. The results showed that hydrocerussite (Pb3(CO3)2(OH)2) and bismutite (Bi2O2(CO2)3) nanostructures were obtained, demonstrating that carbonates can be obtained from metals and metal oxide sources.

Effect Of Annealing On The Structural, Surface Morphology And Optical Properties For CdO:PbO Composite Thin Films

Thin films of pure cadmium oxide films (CdO) and composite with lead oxide (PbO) at different atomic ratios were prepared by pulsed laser deposition under vacuum usingpulsed laser of ND-YAG from CdO and CdO:PbO targets. The prepared thin films were characterized by different technique before and after annealing. The X-ray diffraction shows polycrystalline structures of cubic CdO phase convert tosample of mixed phases for composites. The AFM images illustratedecreasing the particle diameter and increasingsurface roughness with increasing the PbO ratio in composite. While, annealing cause to increase the particle size and reduce roughness. The optical absorbance increased with the PbO ratio, while the absorbance decreased with annealing. The energy gap reduced after annealing and increased with increasing the molar ratio of PbO. These variation in some fundamental properties of the prepared thin films by simplyvarying the components of the started target show the possibilityof controlling the properties of the prepared thin films by pulsed laser depositionfor use in many fields.

Determination of the multiple scattered fraction as a function of target thickness

In the present work, the multiple scattered fraction (MSF) was investigated experimentally for HgO and PbO targets of various thicknesses. The targets were excited by 59.54 keV gamma rays emitted f...

Quantitative x-ray spectrometric analysis with peak to Compton ratios

Abstract Standardization with the scattered x-rays compensates several phenomenons as absorption-enhancement effects, particle size, surface texture effects, packing density and some instrument error. In this work, we used the scattered peak ratio method for quantitative analysis. The samples were prepared from PbO and HgO powders. The calibration curves were created from the intensity ratios of I c o h / I C o m p , I L β / I C o m p , I K α 1 / I C o m p and I K α 2 / I C o m p , one for PbO sample and the other for HgO sample, versus concentration in EDXRF (energy dispersive x-ray fluorescence) system. PbO and HgO targets of various concentrations were excited by 59.54 keV γ-rays from a 5 Ci 241Am annular radioactive source in EDXRF system. The emitted and scattered x-rays by samples were counted by an HPGe detector with a resolution of 182 eV at 5.9 keV at a scattering angle of 168°. Also, WDXRF (wavelength dispersive x-ray fluorescence) system was used to compare the concentrations determined by using EDXRF system. It can conclude that the peak to Compton ratio is highly reliable for quantitative analysis and the calculated concentrations are in good agreement with the EDXRF and WDXRF results. This work is important because PbO and HgO are used extensively as shielding material and catalyst in the chemical reactions.

The Effects of Oxygen Partial Pressure on Interface States and Ferroelectric Properties of PZT/PbO/Si (MFIS) Structures

Pt/PZT/PbO/Si with the MFIS structure was deposited on the p-type (100) Si substrate by the r.f. magnetron sputtering method with Pb1.1Zr0.53Ti0.47O3 and PbO targets. From the X-ray photoelectron spectroscopy (XPS) results, we could confirm that the partial pressure ratio during PbO deposition affects the interface condition of PbO/Si and the chemical state of Pb existing at the surface of the PZT thin film. The maximum value of the memory window is 3.0 V under the applied voltage of 9V for Pt/PZT (200 nm 400°C)/PbO (80 nm, 300°C)/Si structures with the PbO buffer layer deposited at the partial pressure of 7:3. From these results, we could assume that the PbO buffer layers play a role of the diffusion barrier between the PZT thin film and the Si substrate as well as the seed layer.

Epitaxial growth of PbFe12O19 thin films by alternating target laser ablation deposition of Fe2O3 and PbO

Oriented M-type hexaferrite thin films are deposited using the alternating target laser ablation deposition (ATLAD) technique utilizing PbO and Fe2O3 targets. Crystallographic, dc magnetic, and microwave characterization results confirming the presence of a hexagonal PbFe12O19 phase are presented. We conclude that the ATLAD technique holds great promise for layer by layer deposition of various hexaferrite materials, the properties of which can be adjusted by varying the composition of the targets as well as the number of laser shots from each target during the deposition process. This would provide control over the uniaxial anisotropy fields and saturation magnetization values that was not possible in the conventional single target LAD technique.

Thermionic electron emission enhancement of PZT thin films sputter deposition

In this study, PZT thin films are deposited using a novel dual-target (PZT/PbO) RF magnetron sputtering system coupled with plasma enhancement by hot filament thermionic electron emission. The plasma enhancement is expected to allow the deposition temperature to be decreased while retaining the desired properties of the PZT thin films. The influence of the intensified plasma to the structure of the deposited PZT films is investigated and correlated to its ferroelectric properties. The results show that with thermionic enhancement, high remnant and saturation polarization values of 31 μC/cm 2 and 76 μC/cm 2, respectively, are obtained at a deposition temperature of 550 °C if the higher PZT to PbO target power ratio is used; polarization behavior is not observed for the same deposition temperature without thermionic support. For the lower PZT to PbO target power ratio, improved polarization behavior is observed for the coating deposited at 580 °C with thermionic support. Moreover, film growth rate at this power ratio is increased on average by a factor of 1.7 with thermionic enhancement. This study presents the possibility of utilizing a thermionically enhanced plasma to aid in the deposition of ferroelectric PZT thin films by allowing either the deposition time or temperature to be reduced.

THE EFFECT OF THE DEPOSITION CONDITION OF THE PbO BUFFER LAYER ON THE INTERFACIAL CONDITION OF Pb1.1Zr0.53Ti0.47O3/PbO/Si STRUCTURES

ABSTRACT Pt/PZT/PbO/Si (MFIS) structure was deposited on the p-type (100) Si substrate by the r.f. magnetron sputtering method with Pb1.1Zr0.53Ti0.47O3 and PbO targets. From the X-ray photoelectron spectroscopy (XPS) results, we could confirm that the substrate temperature of PbO affects the chemical states of the interface between the PbO buffer layer and Si substrate, which results in the inter-diffusion of Pb and the formation of the intermediate phases (PbSiO3). And we could confirm that the partial pressure ratio during PbO deposition affects the interface condition of PbO/Si and the chemical state of Pb existing at the surface of the PZT thin film.

Preparation and properties of Pb(Zr, Ti)O 3 thin films deposited on Ir electrodes using a sputtering apparatus

Pb(Zr, Ti)O 3 films were prepared on Ir/SiO 2/Si substrates at the substrate temperatures from 450°C to 600°C by a conventional rf diode sputtering system using a ZrTi+ xPbO composite target. X-ray diffraction analysis showed that the crystallinity of films deposited with a ZrTi+24% PbO target was better than that of films deposited with a ZrTi+30% PbO target. The dielectric properties of the PZT films deposited on an Ir/SiO 2/Si substrate at 600°C with a ZrTi+24% PbO target with Au top electrodes were evaluated before and after the annealing at 400°C 10 min in an O 2 atmosphere. The value of remanent polarization obtained from the P– E hysteresis loop characteristics improved from 4.2 μC/cm 2 before annealing to 16.2 μC/cm 2 after annealing at an electric field of 180 kV/cm. The Ti buffer layer improved the crystallinity and/or microstructure of the PZT and Ir films, as evaluated by X-ray diffraction analyses, and reduced the leakage current of the PZT thin films.

Recent progress in sputtering PZT thin films for ferroelectric memories

This paper describes amorphous Pb(Zr, Ti)O3 (PZT) thin films deposited by cosputtering Pb(Zr0.5 Ti0.5)O3 and PbO targets. By optimizing the amount of the excess Pb and the deposition temperature, PZT thin films with a single perovskite phase were obtained successfully on Ir substrates and Pt substrates at 520°C. 250-nm-thick PZT films crystallized by rapid thermal annealing (RTA) at 600°C for 20 s exhibited excellent ferroelectric properties: a coercive voltage of 1.0 V, a remanent polarization density of about 40 μC/cm2, and a polarization switching endurance over 1x109 cycles. Although a heat treatment in a reductive ambient causes degradation of ferroelectric properties of PZT thin films, their degraded ferroelectric properties can be easily recovered from by a 1-min RTA in an oxygen at 400°C.

Effects of Excess Pb and Substrate on Crystallization Processes of Amorphous Pb(Zr, Ti)O3 Thin Films Prepared by RF Magnetron Sputtering

Effects of excess Pb and substrate on the crystallization processes of amorphous lead-zirconate-titanate (a-PZT) thin films by post-annealing in oxygen ambient were investigated to lower the crystallization temperature of the films with a single perovskite phase. A-PZT films were prepared on Ir and Pt substrates with a 2-nm-thick Ti buffer layer on their surfaces, and on a SrRuO3 substrate by cosputtering Pb(Zr0.5Ti0.5)O3 and PbO targets. Analyses by in situ heating X-ray diffraction revealed that the crystallization processes strongly depend on the amount of excess Pb contained in the as-prepared a-PZT and substrates. By controlling the rf power supplied to the PbO target during the deposition, we obtained single perovskite phase PZT films at 480° C, 520° C and 580° C on SrRuO3, Ir and Pt substrates, respectively. The crystallized PZT films exhibited excellent ferroelectric properties. For the 150-nm-thick PZT film, crystallized by rapid thermal annealing at 600° C for 20 s, we obtained a coercive field of 40 kV/cm (0.6 V), a remanent polarization density of 15 µ C/cm2 and polarization switching endurance over 1×109 cycles with Ir top and bottom electrodes.

Preparation and Properties of (Pb, Ca)TiO3 Thin Films by Multiple-Cathode Sputtering

(Pb, Ca)TiO3 (PCT) thin films were fabricated by multiple-cathode RF-magnetron sputtering, using PbO, CaTiO3 and Ti metal targets. PCT films deposited on Pt/Ti/SiO2/Si and Pt/MgO at the substrate temperature from 460° C to 540° C had perovskite structures. The relationship between the substrate temperature and the film properties were investigated. The remanent polarization, dielectric constant and leakage current of the 200-nm-thick PCT(Ca/Ti=0.30) thin films deposited on Pt/Ti/SiO2/Si at 460° C and on Pt/MgO at 500° C were 22.5 µ C/cm2 225 and on the order of 10-7 A/cm2 (at a field of 250 kV/cm), 41 µ C/cm2, 174 and on the order of 10-7 A/cm2 (at a field of 250 kV/cm), respectively.

Analysis of Sputter Process on a New ZrTi+PbO Target System and Its Application to Low-Temperature Deposition of Ferroelectric Pb(Zr,Ti)O3 Films

An rf reactive sputter deposition technique was adopted to deposit ferroelectric lead zirconate titanate (PZT) thin films from a ZrTi (50%/50%) alloy target combined with PbO pellets. Deposition characteristics including the effects of PbO area ratio were discussed. A new deposition mode called the near-metallic mode was observed. The crystallinity and the composition of the films prepared in the near-metallic mode were investigated as functions of PbO area ratio and substrate temperature. Excess Pb supply tended to enhance perovskite phase formation. Near-stoichiometric perovskite PZT films were obtained at a substrate temperature as low as 450° C. On the other hand, for a PZT+PbO target, perovskite PZT films were obtained only at temperatures higher than 540° C. Deposition rate of perovskite films from the ZrTi+PbO target was 2–3 times higher than that from the PZT+PbO target.

Characterization of (Pb1-xLax)TiO3 thin films grown by radio-frequency magnetron sputtering and their electrical properties

Abstract Microstructure, composition, and electrical properties were investigated for polycrystalline (Pb,La)TiO3 (PLT) thin films deposited from the 10 and 20 mol% excess PbO targets. The compositional analysis by Rutherford backscattering pectroscopy shows that PLT films from 20 mol% excess PbO have almost stoichiometric composition and a dense structure. The dielectric constant and a dissipation factor of PLT films from 20 mol% excess PbO were 640 and 0.02 at 100 kHz, respectively. The conduction behavior of PLT films from 10 mol% excess PbO suggested a bulk-limited Poole-Frenkel emission in the high field region, while from 20 mol% excess PbO induced a electrode-limited Schottky emission.

Low-Temperature Fabrication of Pb(Zr,Ti)O 3 Films by RF Reactive Sputtering Using Zr/Ti + PbO Target

Pb(Zr,Ti)O3 (PZT) films were grown on fused quartz substrates by reactive sputtering using a Zr/Ti (50%/50%) alloy target combined with PbO pellets under argon pressure of 10mTorr and O2/Ar flow rate ratio of 2.1%. Structure and deposition rate of the films have been investigated as functions of substrate temperature and PbO content. When films were grown in near metallic mode using a Zr/Ti + 41%PbO target, perovskite PZT films were successfully prepared at a temperature as low as 450°C, and in the wide range from 450°C to 570°C. It was impossible to obtain perovskite PZT films using only a stoichiometic Pb(Zr0.5Ti0.5)O3 ceramic target, while perovskite PZT films could be obtained between 540°C and 570°C using a Pb(Zr0.5Ti0.5)O3 + 15%PbO target. Deposition rate of perovskite films for the Zr/Ti + 41%PbO target was 2–3 times higher than that for the PZT + 15%PbO target.

Multiband analysis of photoluminescence spectra from electronically excited gas-phase species produced during laser ablation of lead oxide, zirconium oxide, titanium oxide, and lead zirconate titanate targets

The analysis of multiband/line photoluminescence spectra produced by electronically excited gas-phase species in the plasma plume, generated by impact of a KrF excimer laser beam (248 nm) on various metal oxide targets, has been carried out, and the results are reported. It was established that, at 1.1 J/cm{sup 2} in 900 mTorr of O{sub 2}, (i) Pb(I), Pb(II), and O{sub 2}{sup +} are generated from PbO(s) targets; (ii) Zr(I), Zr(II), ZrO, O{sub 2}, and O{sub 2}{sup +} from ZrO{sub 2}(s) targets; (iii) Ti(I), Ti(II), TiO, TiO{sub 2}, and O{sub 2}{sup +} from TiO{sub 2}(s) targets; and (iv) Pb(I), Pb(II), PbO, Zr(I), Zr(II), ZrO, Ti(I), Ti(II), TiO, TiO{sub 2}, O(I), O(II), O{sub 2}, and O{sub 2}{sup +} from a solid Pb(Zr{sub x}Ti{sub 1-x})O{sub 3}(PZT) target. The observation of excited oxygen species may be attributed to the presence of ambient molecular O{sub 2} and/or the oxygen-rich metal oxide and PZT targets. The much lower standard enthalpy of atomization, {Delta}H{sub a}{sup 0}, for PbO(s) and the much higher {Delta}H{sub a}{sup 0} values for ZrO{sub 2}(s) and TiO{sub 2}(s) are consistent with observing molecular metal oxide species, MO{sub n}(g), in the ablation plume from ZrO{sub 2}(s) and TiO{sub 2}(s) but observing almost exclusively atomicmore » Pb(I) and Pb(II) from the PbO(s) target. Additionally, a detailed explanation regarding the observation of lower-charged atomic metal species and not the higher-charged (formally ionic) species is presented. Particle ejection is briefly discussed as also is the relative influence of the observed species on thin-film deposition. 30 refs., 4 figs., 8 tabs.« less

Preparation of Pb(Zr, Ti)O3 Thin Films by Multitarget Sputtering

Thin lead zirconate titanate [PZT] (Zr/Ti=50/50) films (230–430 nm) were deposited by multitarget sputtering with three stoichiometric PZT targets and one PbO target. To control Pb content in film, the rf power for the PbO target was varied. The rf power for each PZT target was also varied to control the deposition rate. PZT films with single perovskite phase or dominant perovskite phase were obtained only when the film composition was self-controlled. Low deposition rate resulted in a wider range of PbO input power in which Pb/(Zr+Ti) ratio was almost constant. Therefore low deposition rate would enhance the self composition control (SCC) mechanism. A 240-nm-thick PZT film deposited under the SCC mechanism and low deposition rate showed remanent polarization of 21.5 µ C/cm2, dielectric constant of 600 and leakage current of 7.0×10-8 A/cm2.

Synthesis of (BiPb)2Sr2Ca2Cu3O10 superconducting thin films on MgO using a multilayered pulsed laser deposition method

Superconducting thin films of Pb-doped BiSrCaCuO have been prepared on (001) orientation MgO substrates by a multilayer pulse laser deposition technique using both BiPbSrCaCuO and PbO targets. The PbO target was used to dope Pb into the films in sufficient quantity to facilitate the growth of the 2223 phase. The effect of post-annealing temperature and time duration on the formation of this phase is described. Using x-ray diffraction and resistivity measurements we have found that a near optimum single phase 2223 film can be grown by post-annealing the sample at 854 °C for 15 h in air. The films grown are highly c-axis oriented and exhibit Tc(zero) as high as 105.5 K.

Synthesis and characterization of Pb (ZrxTi1−x)O3 thin films produced by an automated laser ablation deposition technique

Ferroelectric lead zirconium titanate [Pb (ZrxTi1−x)O3] (PZT) thin films have been synthesized by using an automated laser ablation deposition technique with a capability for layer-by-layer or simultaneous deposition of elemental film constituents. The technique is suitable for producing multicomponent and/or multilayered thin films with controlled stoichiometry, such as high-temperature superconductor, ferroelectric, and electro-optic thin films. PZT films were synthesized on MgO (100) by either sequential deposition of layers of ZrO2, TiO2, and PbO, produced by laser ablation of ZrO2, TiO2, and PbO targets, or by simultaneous deposition of all species from ablation of stoichiometric or PbO-rich PZT targets. Films were deposited at 200 °C and subsequently annealed at 600 °C for different periods of time. The orientation, microstructure, surface topography, and composition of the films were characterized by x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Rutherford backscattering spectrometry, respectively. As-deposited layer films consists of highly oriented (001) PbO layers, from which highly oriented (110) PZT films are produced after postdeposition annealing. On the other hand, laser ablation of bulk PZT targets yields amorphous as-deposited films, which evolve into highly oriented (100) PZT films after postdeposition annealing. Preliminary electrical characterization of the PZT films included polarization hysteresis, fatigue, conductivity (ac and dc), and capacitance versus voltage measurements. From the initial electrical measurements, it appears that the remnant polarization of the layered PZT films is similar to that of the films produced by laser ablation of bulk PZT targets.

Pb(Zr, Ti)O3 Thin-Film Preparation by Multitarget Magnetron Sputtering

Ferroelectric lead zirconate-titanate (PZT) thin films have been prepared on Pt-coated oxidized Si substrates (Pt/Ti/SiO2/Si) utilizing a multitarget magnetron sputtering system with three Pb(Zr0.5, Ti0.5)O3 targets and one PbO target. Crystal structure and dielectric properties of the films have been studied as functions of substrate temperature (Ts) and Pb content. The Pb content in the film has been precisely controlled by optimizing the rf input power for the PbO target (PPbO). As a result, single-phase perovskite films have been prepared fairly easily with appropriate combinations of Ts and PPbO. A film with atomic ratios of Pb/(Zr+Ti)=1.3 and Zr/(Zr+Ti)=0.5 prepared at Ts=600°C exhibited a dielectric constant of 780 and remanent polarization of 19 µC/cm2.