Materials Science
Mostafa M. Ibrahim; Mustafa A. Hassan; Khaleel I. Hassoon
Abstract
In this work, the physical properties of iron sulfide (FeS2) thin films deposited by the chemical spray-pyrolysis (CSP) technique were studied. The thin films are deposited on glass substrates at 200oC, using FeCl3 salt with thiourea (NH2)2CS as precursors. Structural analysis of X-Ray diffraction ...
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In this work, the physical properties of iron sulfide (FeS2) thin films deposited by the chemical spray-pyrolysis (CSP) technique were studied. The thin films are deposited on glass substrates at 200oC, using FeCl3 salt with thiourea (NH2)2CS as precursors. Structural analysis of X-Ray diffraction manifested that the thin films contain two phases: Marcasite and Pyrite in planes (110), (111) at angles 2θ =26.3°, 2θ =28.3° respectively. Optical properties analysis showed that the prepared iron sulfide thin-films were highly absorbing in the UV-Visible range and the absorption coefficient was in the range of 1.6x105 cm-1 with a relatively low resistivity of about 0.49 (Ω.cm). The calculated activation energy (Ea) was 0.024 eV and the bandgap value was 2.45 eV. Moreover, the FeS2 thin films were also deposited on (CdO) to fabricate a heterojunction photocell. In conclusion, there is the feasibility of preparing low-cost and highly absorbing iron sulfide (FeS2) thin films for optoelectronic applications with acceptable homogeneity using the spray-pyrolysis technique.
Laser Science and Technology
Hajir M. Fadhil; Hyder A. Salih; Khaleel I. Hassoon
Abstract
In the present work, Laser Induced Breakdown Spectroscopy (LIBS) has been utilized to investigate two forms of aluminum samples, namely Al in the form of the nanoparticles (NPs) and a bulk (pellet). The Al target was irradiated by pulsed Nd-YAG laser with wavelength 1064 nm to produce plasma. The plasm ...
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In the present work, Laser Induced Breakdown Spectroscopy (LIBS) has been utilized to investigate two forms of aluminum samples, namely Al in the form of the nanoparticles (NPs) and a bulk (pellet). The Al target was irradiated by pulsed Nd-YAG laser with wavelength 1064 nm to produce plasma. The plasm spectrum is analyzed in the wavelength range between 250 nm and 700 nm. Some plasma parameters were calculated, including electron temperature (𝑇𝑒), plasma density (ne) and Debye length (𝜆𝐷) for different laser energies. The temperature of electrons was computed employing the Boltzmann plot technique, and the electrons density was computed utilizing the Stark broadening technique. This work aims to investigate the effect of laser energy on the plasma parameters and the influence of using two different forms of targets on these parameters. It was noted that increasing the laser energy from (400 mJ) to (700 mJ) resulted in an increase in electrons temperaturefrom (0.52 eV) to (0.65 eV) and an increase in electron density from (57.38×1016 cm-3) to (67×1016 cm-3) for the nano aluminum plasma, whereas the electrons temperature increased from (0.52 eV) to (0.59 eV) and the electron density increased from (43.88×1016 cm-3) to (55.05×1016 cm-3) for the bulk aluminum plasma.From the obtained results, it's concluded that using identical laser energies, the electron temperature and electron density of the plasma generated from aluminum in the form of nanoparticles are greater than that generated from aluminum in the bulk form. The differences in the calculated parameters for Al NPs and Al bulk belong to their different structures and morphologies as presented via Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) methods.
