Spatial profile of Al-ZnO thin film on polycarbonate deposited by ring-shaped magnetized rf plasma sputtering with two facing cylindrical Al2O3 - ZnO targets

Radial profiles of the ion saturation current are measured in a ring-shaped magnetized radio-frequency plasma sputtering process with two facing cylindrical ZnO targets including Al2O3 (2% wt.). The profile has a non-uniform shape with a peak whose position corresponds to the target near the electrode due to the effect of the magnetic field distribution. It becomes uniform at large distances between the substrate and a target (d st ≥ 50 mm). The radial profile of the resistivity of the Al-ZnO (AZO) films deposited on a polycarbonate plate at Ar gas pressure of 0.27 Pa is uniform at about 10-3 Ω·cm for d st ≥ 50 mm. The films deposited at various positions and room-substrate-temperature also show a good crystallinity based on an X-ray diffraction peak of about 33.95 - 34.44°. The grains exhibit a preferential orientation along the [002] axis with its size ranging from 18.15 to 28.17 nm. A higher transmittance of 95.6 % in the visible region is also obtained.

Sulfurization of Electrodeposited Sb/Cu Precursors for CuSbS2: Potential Absorber Materials for Thin-Film Solar Cells

CuSbS2, as a direct bandgap semiconductor, is a promising candidate for fabricating flexible thin-film solar cells due to its low grain growth temperature (300°C–450°C). Uniform and highly crystalline CuSbS2 thin films are crucial to improving device performance. However, uniform CuSbS2 is difficult to obtain during electrodeposition and post-sulfurization due to the “dendritic” deposition of Cu on Mo substrates. In this study, Sb/Cu layers were sequentially pulse electrodeposited on Mo substrates. By adjusting the pulse parameters, smooth and uniform Sb layers were prepared on Mo, and a flat Cu layer was obtained on Sb without any dendritic clusters. A two-step annealing process was employed to fabricate CuSbS2 thin films. The effects of temperature on phases and morphologies were investigated. CuSbS2 thin films with good crystallinity were obtained at 360°C. As the annealing temperature increased, the crystallinity of the films decreased. The CuSbS2 phase transformed into a Cu3SbS4 phase with the temperature increase to 400°C. Finally, a 0.90% efficient solar cell was obtained using the CuSbS2 thin films annealed at 360°C.

Preparation and Characterization ZnO Nanorods for Photocatalyst Application

Zinc oxide (ZnO) nanorods are prepared onto glass substrates via chemical bath deposition method. ZnO nanoparticles is prepared onto glass substrate to act as a seed layer for grown ZnO NRs. Field Emission Scanning Electron Microscope (FESEM) image confirmed that the grown rods have hexagonal shape covered the surface of substrate. Further, the prepared ZnO NRs appeared good crystallinity according to X-ray diffraction method. The absorption edge for seeds nanoparticles layer appeared at wavelength of 362nm (3.42 eV) while it was at around 479nm (3.27 eV) nm for the grown ZnO NRs. The grown ZnO NRs showed two emission peaks at 381nm and 540nm corresponding to near band-to-band electron-hole recombination and oxygen vacancies, respectively. Degradation rate of methylene blue (MB) dye was 0.01% after 1h of illumination by UV light and increased to 71.4% after 4h of illumination.

Preparation of complex oxide (Pr0.8Y0.2)0.6Ca0.4CoO3 from Pr–Y–Ca–Co gel synthesized by ultrasonic irradiation and its metal-insulator transition characteristics

We previously reported that a swollen gel possessing a uniform composition and prolonged stability can be conveniently prepared by simple ultrasonic irradiation of an ethanol suspension of calcium acetate, which is poorly soluble in ethanol. In this study, the same gel synthesis method was applied to prepare the multicomponent oxide (Pr1−yYy)1−xCaxCoO3 (PYCCO), which undergoes a metal-insulator phase transition. Calcination of the Pr–Y–Ca–Co swollen gel at 800 °C for 12 h in air afforded PYCCO nanoparticles with good crystallinity, representing a faster and more convenient route compared with conventional solid-phase reaction methods or sol–gel methods.

Evaluation of Crystalline Volume Fraction of Laser-Annealed Polysilicon Thin Films Using Raman Spectroscopy and Spectroscopic Ellipsometry

We investigated the crystallinities of poly silicon (poly Si) annealed via green laser annealing (GLA) with a 532-nm pulsed laser and blue laser annealing (BLA) with 450-nm continuous-wave lasers. Three-dimensional heat transfer simulations were performed to obtain the temperature distributions in an amorphous silicon (a-Si) thin film, and GLA and BLA experiments were conducted based on the thermal simulation results. The crystallinity of annealed poly Si samples was analyzed using Raman spectroscopy and spectroscopic ellipsometry. To evaluate the degree of crystallization for the annealed samples quantitatively, the measured spectra of laser-annealed poly Si were fitted to those of crystalline Si and a-Si, and the crystal volume fraction (fc) of the annealed poly Si sample was determined. Both the Raman spectroscopy and ellipsometry showed consistent results on fc. The fc values were found to reach >85% for optimum laser power of GLA and BLA, showing good crystallinity of the laser-annealed poly Si thin films comparable to thermal furnace annealing.

A Comparative Study of Nanostructures of CuO/Cu2O Fabricated via Potentiostatic and Galvanostatic Anodization

A detailed comparative study on the synthesis process of coral-like CuO/Cu2O nanorods (NRs) and nanopolycrystals (NPCs) fabricated on Cu foil employing aqueous electrolyte via potentiostatic (POT) and galvanostatic (GAL) modes is discussed. The structural, morphological, thermal, compositional, and molecular vibration of the prepared CuO/Cu2O nanostructures was characterized by XRD, HRSEM, TG/DTA, FTIR, and EDX techniques. XRD analysis confirmed the crystalline phase of the formation of monoclinic CuO and cubic Cu2O nanostructures with well-defined morphology. The average particle size was found to be 21.52 nm and 26.59 nm for NRs (POT) and NPCs (GAL), respectively, and this result is corroborated from the HRSEM analysis. POT synthesized nanoparticle depicted a higher thermal stability up to 600°C implying that the potentiostatically grown coral-like NRs exhibit a good crystallinity and well-ordered morphology.

Effect of precursor particle size and morphology on lithiation of Ni0.6Mn0.2Co0.2(OH)2

In this paper, Ni0.6Mn0.2Co0.2(OH)2 precursors with several different morphologies and particle sizes are mixed with Li2CO3 and heat treated for 5, 7.5 and 10 h. The effects of the precursor properties on the degree of lithiation, electrochemical properties and volumetric capacities of lithiated product are compared. Based on the characterization results, a small (3 μm), narrow span precursor can be lithiated in a short period of time (5 h) and has good initial discharge capacity (185 mA h g− 1) and capacity retention (93% for 55 cycles). In contrast, a large wide-span precursor requires over 10 h for full lithiation. A highly porous precursor can be lithiated faster than traditional large wide-span materials, and has low cation mixing and good crystallinity. However, the volumetric energy density of porous material is low after lithiation compared to the other tested materials. Capacity retention after washing correlated with crystallographic properties of the sample. Graphic abstract

Wound-Healing Properties of Green (Using Lawsonia Inermis Leaf Extract) and Chemically Synthesized Zno Nanoparticles in Albino Rats

Wound healing is one of the utmost medical issues in human and veterinary medicine, which explains the urgent need for developing new agents that possess wound-healing activities. The present study aimed to assess the effectiveness of green and chemical ZnO-NPs for wound healing. ZnO-NPs (chemical and green using Lawsonia inermis leaf extract) were synthesized and characterized by XRD; FTIR, and HRTEM. The gels containing the nanomaterials were prepared and inspected. Forty-five albino rats were divided into three groups, the control group was treated with normal saline 0.9 % and the other two groups were treated with gels containing green and chemical ZnO-NPs, respectively. On the 3rd, 7th, 14th, and 21st dpt, the wounds were clinical and histologically examined. Both nanomaterials have good crystallinity and high purity, but green ZnO-NPs have a longer nanowire length and diameter than chemical ZnO-NPs. The formed gels were highly viscous with a pH of 6.5 to 7. Both prepared gels showed clinical improvements, such as a decrease in WSA and WSA%, increase in WC%, and reduced healing time (P < 0.05) in both treated groups when compared with control group. The histological scoring of this study showed that the epithelization score was significantly higher at 21st dpt in treated groups than in the control group (P < 0.05), but the vasculature, necrosis, connective tissue formation, and collagen synthesis scores were mostly similar. The green and chemical ZnO-NPs gels showed promising wound healing properties however, the LI mediated-ZnO-NPs were more effective.

Effect of Annealing Temperature on Microstructure and Resistivity of TiC Thin Films

Titanium carbide (TiC) thin films were prepared by non-reactive simultaneous double magnetron sputtering. After deposition, all samples were annealed at different temperatures under high-vacuum conditions. This paper mainly discusses the influence of deposition methods and annealing temperatures on microstructure, surface topography, bonding states and electrical resistivity of TiC films. XRD (X-ray diffraction) results show that TiC thin films can still form crystals without annealing, and the crystallinity of thin films is improved after annealing. The estimated grain size of the TiC films varies from 8.5 nm to 14.7 nm with annealing temperature. It can be seen from SEM (scanning electron microscope) images that surfaces of the films are composed of irregular particles, and when the temperature reaches to 800 °C, the shape of the particles becomes spherical. Growth rate of film is about 30.8 nm/min. Oxygen-related peaks were observed in XPS (X-ray photoelectron spectroscopy) spectra, which is due to the absorption of oxygen atoms on the surface of the film when exposed to air. Raman spectra confirm the formation of TiC crystals and amorphous states of carbon. Resistivity of TiC films decreases monotonically from 666.73 to 86.01 μΩ·cm with the increase in annealing temperature. In brief, the TiC thin films prepared in this study show good crystallinity, thermal stability and low resistivity, which can meet the requirements of metal gate applications.

Fabrication Techniques for Quantum Dots

The nanotechnological expansion involves the innovation and designing of materials at the nanoscale regime with controlled properties. Production of nanomaterials with good crystallinity, shape control, and narrow distribution of size plays a significant role in QD-based devices and applications. Various strategies ranging from simple wet chemical methods to advanced atomic layer deposition strategies have been employed for the production of QDs. In this chapter, a prominent and detailed discussion of conventional techniques in addition to the up-to-date development in the synthesis of recent QDs is given. Synthesis routes based on the microwave or ultrasonically assisted and cluster-seed process are of great significance.