Computational and experimental analysis of the optical properties of β-Si3N4 doped Be, Ca, Ba and Eu

Abstract

Based on first-principles calculations, we have studied the structural, electronic and optical properties of Be, Ca, Ba, and Eu doped β-Si3N4 systems. Firstly, after performing the structure optimization of the doped systems, the stability of the doped systems is verified via the calculation of the formation energy. Then, the electronic properties of the doped systems are studied based on the band structure and density of states. Compared with pure β-Si3N4, the bandgap of the doped systems becomes narrowed. Particularly the bandgap of the Eu-doped system is reduced to 0.209 eV due to the Eu 4f orbital, which broadens the development prospects of the application of Si3N4 materials in the semiconductor field. Meanwhile, the dielectric function, absorption and reflection coefficient are discussed to evaluate the optical properties of the doped systems. Finally, the verified experiment was carried out by a spark plasma sintering, according to the simulations results that the Eu doped system shows the potential for visible light absorption. The research provides both the theoretical and experimental bases for the preparation of color Si3N4 ceramics.