Optical properties of fluorinated boron nitride monolayers

Abstract

In the present work, the optical properties of fluorinated BN monolayers as well as the effect of typical point defects, namely, anti-sites, substitutional carbon impurities and fluorine vacancies, were investigated using first principles calculations. It has been considered fluorinated nanosheets in both chair-like and boat-like configurations. The obtained results indicate that the fully fluorinated monolayers (termed as BN-difluorine) are semiconductors with high transmissivity and just absorb and conduct in the ultraviolet range. Besides, chair-like monolayers have a transmissivity higher than their boat-like counterparts due to the fact that they absorb and reflect less. The introduction of a point defect on the BN-difluorine layer, for both configurations, significantly modifies its optical properties in the low energy range, where absorption and conduction is induced in the whole infrared and visible regions, depending upon the defect. By contrast, at higher energies, the optical spectra of the defective BN-difluorine monolayers are quite similar to the undefective ones.