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1.
Materials (Basel) ; 16(8)2023 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-37109916

RESUMO

The microstructural, electrical, and optical properties of Cu-doped and undoped ZnTe thin films grown on glass substrates are covered in this article. To determine the chemical makeup of these materials, both energy-dispersive X-ray (EDAX) spectroscopy and X-ray photoelectron spectroscopy were employed. The cubic zinc-blende crystal structure of ZnTe and Cu-doped ZnTe films was discovered using X-ray diffraction crystallography. According to these microstructural studies, the average crystallite size increased as the amount of Cu doping increased, whereas the microstrain decreased as the crystallinity increased; hence, defects were minimized. The Swanepoel method was used to compute the refractive index, and it was found that the refractive index rises as the Cu doping levels rises. The optical band gap energy was observed to decrease from 2.225 eV to 1.941 eV as the Cu content rose from 0% to 8%, and then slightly increase to 1.965 eV at a Cu concentration of 10%. The Burstein-Moss effect may be connected to this observation. The larger grain size, which lessens the dispersion of the grain boundary, was thought to be the cause of the observed increase in the dc electrical conductivity with an increase in Cu doping. In structured undoped and Cu-doped ZnTe films, there were two carrier transport conduction mechanisms that could be seen. According to the Hall Effect measurements, all the grown films exhibited a p-type conduction behavior. In addition, the findings demonstrated that as the Cu doping level rises, the carrier concentration and the Hall mobility similarly rise, reaching an ideal Cu concentration of 8 at.%, which is due to the fact that the grain size decreases grain boundary scattering. Furthermore, we examined the impact of the ZnTe and ZnTe:Cu (at Cu 8 at.%) layers on the efficiency of the CdS/CdTe solar cells.

2.
Materials (Basel) ; 16(6)2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-36984104

RESUMO

After (In1-xGdx)2O3 powder with a wide x range of 0 to 10 at.% was chemically produced, (In1-xGdx)2O3 thin films were evaporated under ultra-vacuum using an electron beam apparatus. We investigated the influence of the Gd doping concentration on the magnetic, optical, electrical, and structural properties of the resultant In2O3 deposits. The produced Gd-doped In2O3 films have a cubic In2O3 structure without a secondary phase, as shown by the X-ray diffraction results. Additionally, the chemical analysis revealed that the films are nearly stoichiometric. A three-layer model reproduced the spectroscopic ellipsometer readings to determine the optical parameters and energy gap. The Egopt changed toward the lower wavelength with growing the Gd doping in (In1-xGdx)2O3 films. The Egopt in the (In1-xGdx)2O3 films was observed to increase from 3.22 to 3.45 eV when the Gd concentration climbed. Both carrier concentration and hall mobility were found during the Hall effect studies. It was possible to construct the heterojunction of Ni (Al)/n-(In1-xGdx)2O3/p-Si/Al. At voltages between -2 and 2 volts, investigations into the dark (cutting-edge-voltage) characteristics of the produced heterojunctions were made. The oxygen vacancies and cationic defects in the lattice caused by the uncompensated cationic charges resulted in significant magnetism and ferromagnetic behavior in the undoped In2O3 films. The (In1-xGdx)2O3 films, however, displayed faint ferromagnetism. The ferromagnetism seen in the (In1-xGdx)2O3 films was caused by oxygen vacancies formed during the vacuum film production process. Metal cations created ferromagnetic exchange interactions by snatching free electrons in oxygen.

3.
Materials (Basel) ; 16(7)2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-37048969

RESUMO

Iron-doped Zinc oxide nanoparticles were produced by the sol-gel combustion method. This study aims to see how iron doping affects the structural, optical, and photocatalytic characteristics of ZnO composites. XRD examined all samples to detect the structural properties and proved that all active materials are a single hexagonal phase. The morphology and particle size were investigated by TEM. Computational Density functional theory (DFT) calculation of the band structure, density of state, and charge distributions for ZnO were investigated in comparison with ZnO dope iron. We reported the application results of ZnO doped Fe for Methylene blue dye removal under photocatalytic degradation effect. The iron concentrations affect the active material's band gap, producing higher photocatalytic performance. The acquired results could be employed to enhance the photocatalytic properties of ZnO.

4.
Polymers (Basel) ; 13(22)2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34833351

RESUMO

Zeolitic imidazolate frameworks (ZIFs) are interesting materials for use in several aspects: energy storage material, gas sensing, and photocatalysis. The thermal stability and pyrolysis process are crucial in determining the active phase of the material. A deep understanding of the pyrolysis mechanism is in demand. Therefore, the thermodynamics and combustion process with different heating rates was examined, and the kinetic parameters were computed employing thermogravimetric tests. Based on the TG analysis of combustion, pyrolysis moves to the high-temperature region with an increase in heating rate. The decomposition process can be separated into the dehydration (300-503 K) and the pyrolysis reaction (703-1100 K). Three points of the decomposition process are performed by dynamical analysis owing to shifts of slopes, but the combustion process has only one stage. The Zeolitic imidazolate framework's structure properties were examined using TDDFT-DFT/DMOl3 simulation techniques. Dynamical parameters, for instance, the possible mechanism, the pre-exponential factor, and the apparent activation energy are obtained through comparison using the Kissinger formula. The thermodynamics analysis of the Zn1-xCox-ZIF-8 materials is an effective way to explore the temperature influence on the process of pyrolysis, which can benefit several environment purifications, photocatalyst, and recent applications.

5.
Springerplus ; 3: 443, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25184109

RESUMO

The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined.

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