Spectroscopic and Structural Analysis of Aluminum Bulk and Nanoparticles: A Comparative Study

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 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.

Keywords

• libs
• optical emission spectroscopy
• x-ray diffraction
• scanning electron microscopy