Magnetism, spintronics

Nature of defects responsible for the red shift of the fundamental absorption edge and the increase in the refractive index of irradiated Si$_3$N$_4$

V. A. Gritsenko^ab, Yu. N. Novikov^a, A. A. Gismatulin<sup>a

a</sup> Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk
^b Novosibirsk State Technical University

Abstract: The atomic structure of amorphous silicon nitride Si$_3$N$_4$ irradiated with boron B$^+$ ions is studied using photoelectron spectroscopy and infrared absorption. Irradiation with B$^+$ ions is accompanied by a red shift of the fundamental absorption edge of Si$_3$N$_4$. Irradiation with B$^+$ ions leads to a broadening of the Si 2$s$ atomic level toward lower energies, indicating the formation of Si–Si bonds. The formation of Si–Si bonds due to the splitting of bonding and antibonding orbitals leads to a decrease in the bandgap and an increase in the refractive index.

Keywords: silicon nitride, XPS, fundamental absorption edge, refractive index, Si–Si bonds.

Received: 17.10.2025
Revised: 05.11.2025
Accepted: 05.11.2025

DOI: 10.61011/FTT.2025.11.62137.281-25

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