Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Materials Science Poland

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

UV-Vis studies of 800 keV Ar ion irradiated NiO thin films

Mallick P., Mishra D. K., Kumar P., Kanjilal D.

Materials Science Poland

2015

Vol. 33, No. 3

555--559

We report the evolution of optical absorption properties of 800 keV Ar ion irradiated NiO thin films through UV-Vis characterization. Our results indicate the existence of both Mott-Hubbard (d → d transition) and charge-transfer (p ! d transition) characteristic of NiO. The optical band gap of NiO increases from 3.58 to 3.75 eV when irradiated at the fluence of 5 x 1014 ions cm-2 but it does not show any remarkable variation upon 800 keV Ar ion irradiation at higher fluences. The refractive index and electron polarizability at different ion fluences have been determined from the optical band gap. Both refractive index and electron polarizability follow an opposite trend to that of the energy gap as a function of ion fluence.

Influence of different materials on the microstructure and optical band gap of α-Fe2O3 nanoparticles

Mallick P

Materials Science Poland

2014

Vol. 32, No. 2

193--197

Composites of hematite (a-Fe2O3) nanoparticles with different materials (NiO, TiO2, MnO2 and Bi2O3) were synthesized. Effects of different materials on the microstructure and optical band gap of a-Fe2O3 nanoparticles were studied. Crystallite size and strain analysis indicated that the pure a-Fe2O3 nanoparticles were influenced by the presence of different materials in the composite sample. Crystallite size and strain estimated for all the samples followed opposite trends. However, the value of direct band gap decreased from 2.67 eV for the pure a-Fe2O3 nanoparticles to 2.5 eV for a-Fe2O3 composites with different materials. The value of indirect band gap, on the other hand, increased for all composite samples except for a-Fe2O3/Bi2O3.