Structural and vibrational characterization of Si ₃ N ₄ nanopowders under electron beam irradiation

The structural and vibrational properties of Si₃N₄nanopowders were investigated before and after electron irradiation at fluences of 1 × 10¹⁵, 5 × 10¹⁵, and 1 × 10¹⁶e cm^-2. X-ray diffraction analysis revealed that the material retains its biphasic nature (<i>α</i>- and<i>β</i>-Si₃N₄) after irradiation, although changes in phase fractions and lattice parameters were observed. Fourier-transform infrared spectroscopy (400-1300 cm^-1) showed shifts in peak positions and variations in intensities, indicating bond rearrangements and modifications in the local Si-N and Si-O environment. Raman spectroscopy further confirmed irradiation-induced structural changes through systematic peak shifts and spectral modifications. The results demonstrate that electron irradiation significantly affects the local structure and defect formation in Si₃N₄nanopowders while preserving the overall crystalline phases.