Siligene Monolayer Oxidation and Formation of Wide Band Gap Siligene Oxides for Next-Generation Sensing Technologies

We investigate the initial stages of oxidation in siligene, a two-dimensional nanomaterial made of silicon (Si) and germanium (Ge) honeycomb lattice systems, using first-principles calculations. Our results show that a single oxygen atom preferentially adsorbs at epoxy sites between Si and Ge atoms, independent of whether the surface is Si- or Ge-terminated. When an oxygen molecule interacts with siligene, the dissociation into two separate O atoms is energetically favored. In the most stable configuration, oxygen atoms remain in epoxy positions but bond to the same Si atom with one O atom on each side of the siligene sheet. Furthermore, we explore the formation of an oxidized siligene 2D system by considering various oxygen coverages and structural arrangements. Among the tested configurations, two of them were found to be stable. They consist of bilayers of SiO3Ge, coupled with and without O atoms, forming Si2O8Ge2 and Si2O6Ge2 structures, respectively. The electronic properties of these siligene oxide 2D systems show large band gaps and therefore can be applied in power electronics, optoelectronics, high-frequency communications, and radiation-resistant devices due to their ability to operate at higher temperatures, voltages, and frequencies than silicon. Furthermore, the atomic elements and structural cavities in siligene oxides make them promising candidates for trapping ions and small molecules for next-generation sensing materials applications.