Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Materials Science Poland

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Preparation and characterization of cobalt and copper oxide nanocrystals

Moharram A. H.

Materials Science Poland

2019

Vol. 37, No. 3

347--352

Copper oxide and cobalt oxide (Co3O4, CuO) nanocrystals (NCs) have been successfully prepared using microwave irradiation. The obtained powders of the nanocrystals (NCs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy. The obtained results confirm the presence of both nanooxides which have been produced during chemical precipitation using microwave irradiation. TEM micrographs have shown that the obtained nanocrystals are characterized by high dispersion and narrow size distribution. The results of X-ray diffraction confirmed those obtained from the transmission electron microscope. Optical absorption analysis indicated the direct band gap for both kinds of the nanocrystals.

Photo-induced changes in arsenic selenide films

Moharram A. H., Mansour S. A., Al-Marzouki F., Hendi A. A., Rashad M.

Materials Science Poland

2013

Vol. 31, No. 1

139-145

The spectral dependence of the transmittance and reflectance of thermally-evaporated amorphous AsxSe100x (where x = 20 and 40 at.%) films was measured in the wavelength range of 190 - 900 nm. A procedure was given for accurate determination of the film thickness using a standard method of numerical differences from the experimental data. The process of indirect electronic transitions was found to be responsible for the photon absorption. The variation of the energy band gap with the exposure time was investigated. Amorphous-crystalline transformations occurring as a result of photoexposure have been confirmed by the structural studies of the As20Se80 specimens using the scanning electron microscope and transmission electron microscope. Photodarkening relaxation under light exposure of the well annealed films was studied and the relaxation process has been described by the stretched exponential function (SEF).