Researcher Samah Sameer Attari, a student in the master’s program in physics, has defended her thesis titled “"Iron Doping Effects on Bi_2 O_3 Optical Filters"
This thesis touched upon the effect of iron doping on the structural, morphological, compositional, optical and dielectric properties of bismuth oxide thin films. Bismuth oxide thin films with a thickness of 0.50 μm were deposited by thermal evaporation of bismuth oxide powders on glass substrates under a vacuum pressure of approximately 4-10 mbar. This was followed by doping the films with iron by mixing the iron nano-powders with the bismuth oxide powders before evaporation. The researcher used three increasing amounts of iron for this purpose.
It was noted that the prepared films were polycrystalline in nature and that the grafting process led to a decrease in the size of the crystals and an increase in microscopic damage and defect density. The scanning electron microscope showed grains of increasing sizes and different shapes depending on the amount of iron grafted. Optically, the grafted films showed lower transmittance values and a decrease in the energy band gap with increasing iron content. On the other hand, dielectric dispersion analyzes showed an improvement in the dielectric constant response in proportion to the dielectrics used in thin-film transistor technology, which rely on gates with a high dielectric constant to operate. The imaginary dielectric constant was analyzed using the Drude-Lorentz model, which links electrical information to optical information, and compared to experimental data that showed a decrease in electron density with increasing iron content in bismuth oxide. This research is promising because it enhances the performance of bismuth oxide and makes it suitable for electronic applications.
The thesis was supervised by Prof. Dr. Atef Qasrawi. The committee of examiners included Dr. Iyad Saad El-Din and Prof. Dr. Hazem Khanfar.