Magnesium oxide nanoparticles (MgO NPs) were obtained by the calcination of precursor microparticles (PM) synthesized by a novel triethylamine-based precipitation method. Scanning electron microscopy (SEM) revealed a mean size of 120 nm for the MgO NPs. The results of the characterizations for MgO NPs support the suggestion that our material has the capacity to attack, and have an antibacterial effect against, Gram-negative and Gram-positive bacteria strains. The ability of the MgO NPs to produce reactive oxygen species (ROS), such as superoxide anion radicals (${\mathrm{O}}_2^{•-}$) or hydrogen peroxide (H₂O₂), was demonstrated by the corresponding quantitative assays. The MgO antibacterial activity was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria, with minimum inhibitory concentrations (MICs) of 250 and 500 ppm on the microdilution assays, respectively. Structural changes in the bacteria, such as membrane collapse; surface changes, such as vesicular formation; and changes in the longitudinal and horizontal sizes, as well as the circumference, were observed using atomic force microscopy (AFM). The lipidic peroxidation of the bacterial membranes was quantified, and finally, a bactericidal mechanism for the MgO NPs was also proposed.

In this work, the application of RF power in stepped mode during the growth process of CdTe films deposited on glass substrates at room temperature and their structural, morphological, and optical properties were studied. The working pressure and deposition time during deposition were 10 mTorr and 120 min, respectively, meanwhile the RF power was gradually varied from 30 W to 40 W. For comparison and reference, CdTe films with 30 W and 40 W (fixed power values) were also deposited, which resulted amorphous. The x-ray diffraction results of the films prepared with stepped RF power were polycrystalline with cubic structure and (111) as preferential orientation. The crystallite size of films changes from 16.6 to 29.2 nm as the rate of the stepped RF power increases. Raman spectra show that intensity of peaks located at 123, 140 and 164 cm-1 increase with the increased rate of stepped RF power, as well as the rms-roughness and grain size values increase from 0.8 nm to 1.6 nm and from 62.8 nm to 92.1 nm, respectively. The UV-Vis spectra show that the bandgap energy of the deposited CdTe films changes from 1.47 to 1.54 eV with the increased rate of stepped RF power. The obtained bandgap energy values of the CdTe films are adequate to be used as absorber material for photovoltaic applications into the ZnO/CdTe and CdS/CdTe solar cells.

Amino acid complexes of zirconia represent an entirely new class of materials that were synthesized and studied for the first time for the decontamination of fluoride ion containing aqueous solutions. Glutamic and aspartic acid complexes of zirconia assembled with thin carbon (stacked graphene oxide) platelets deriving from graphite oxide (GO) were synthesized by a two-step method to prepare adsorbents. The characterization of the complexes was carried out using infrared spectroscopy to determine the functional groups and the types of interaction between the composites and fluoride ions. To reveal the mechanisms and extent of adsorption, two types of batch adsorption measurements were performed: (i) varying equilibrium fluoride ion concentrations to construct adsorption isotherms at pH = 7 in the absence of added electrolytes and (ii) using fixed initial fluoride ion concentrations (10 mg/L) with a variation of either the pH or the concentration of a series of salts that potentially interfere with adsorption. The experimental adsorption isotherms were fitted by three different theoretical isotherm equations, and they are described most appropriately by the two-site Langmuir model for both adsorbents. The adsorption capacities of Zr-glutamic acid-graphite oxide and Zr-aspartic acid-graphite oxide are 105.3 and 101.0 mg/g, respectively. We found that two distinct binding modes are combined in the Zr-amino acid complexes: at low solution concentrations, F⁻ ions are preferentially adsorbed by coordinating to the surface Zr species up to a capacity of ca. 10 mg/g. At higher concentrations, however, large amounts of fluoride ions may undergo anion exchange processes and physisorption may occur on the positively charged ammonium moieties of the interfacially bound amino acid molecules. The high adsorption capacity and affinity of the studied dicarboxylate-type amino acids demonstrate that amino acid complexes of zirconia are highly variable materials for the safe and efficient capture of strong Lewis base-type ions such as fluoride.

Aluminum-doped zinc oxide (AZO) thin films were deposited on glass substrates at room temperature by RF sputtering technique. Power ramps between 125 and 105 W were applied with a step of 4 W by intervals of 15, 7.5 and 1.8 min, for 180 min at 1.60 Pa. In this study, we investigated the structural, morphological, electrical, and optical properties of AZO films. X-ray Diffraction analysis showed that the films have a wurtzite-type hexagonal crystalline structure with a preferential crystallographic orientation (002) normal to the c axis. The average transmittance is greater than 76% for the wavelength range in the visible spectrum. The bandgap values were found between 3.32 and 4.01 eV, and refractive index was 1.79–2.60. Atomic force microscope measurements show homogeneous films with a roughness between 17–22 nm. A minimum resistivity value of 2.0 × 10⁻³ Ω cm was obtained for the film by using a power ramp of 4 W/1.8 min.

SiC is a broadly researched and utilized material in a wide variety of known applications like coatings, MOSFETs and other miscellaneous devices; Regardless of this, SiC technology still has potential growth in new material engineering and devices through use of modern growth techniques and methods. In this study, we attempted to deposit SiC films on Si and glass substrates by using low temperature and different R. F. power ramps in a Magnetron Sputtering. The experiment presented successful growth of SiC thin films through a novel ramping method that allowed us to deposit a thin film at room temperature. The films were characterized by using AFM Microscopy, Spectroscopic Ellipsometry and Micro-Raman Spectroscopy. The valuable information obtained on surface morphology, band gap energy and crystal structure will fuel further endeavors to continually develop this material for future applications. AFM measurements presented a periodic grain pattern akin to terraces with quadrilateral grains and a meaningfully different geometry when compared to traditional semiconductor surfaces. Ellipsometry data provided a band gap energy from 3.3 eV. Raman spectra revealed broad peaks pertaining to multiple SiC polytypes.