Optical properties calculations of the phosphorene-CrO 3 system within the G 0 W 0 and BSE approximations

Phosphorene, the two-dimensional counterpart of black phosphorus, is under current intense investigation in order to be applied in gas sensor devices. In regard to the material excited-state properties, these may be sensitive to molecular adsorption. Therefore, in this work we theoretically study the change in the optical properties of phosphorene-CrO 3 systems considering different CrO 3 surface coverage (0.0%, 34.3% and 68.6%). The CrO 3 molecule is a powerful oxidizer and a suspected carcinogen. To determine rigorously the optical properties of CrO 3 adsorbed on a surface is mandatory the use of the G 0 W 0 approximation and the solution of the Bethe-Salpeter equation (BSE) with the inclusion of van der Waals forces. As part of the results, this work shows the electrical band gap values obtained by the application of the G 0 W 0 approximation, optical band gap values derived from the solution of the BSE and an analysis on the optical in-plane anisotropy of the composed phosphorene-CrO 3 systems. Ultimately, results show that the band gap, the optical absorption spectrum and the optical in-plane anisotropy of phosphorene can be broadly tuned by changing the amount of CrO 3 surface coverage and molecular disposition.