Optical properties of F- and H-terminated armchair silicon nanoribbons

The optical properties of F- and H-terminated silicon nanoribbons with armchair edges (F- and H-terminated ASiNRs) are compared by using the first-principles within the density function theory (DFT) framework. The results show that compared with for H-terminated 7-ASiNR, the dielectric function for the F-terminated 7-ASiNR has a red shift, which is mainly attributed to the narrower band gap because of the sigma-pi mixing effect of F-Si bonds in F-terminated 7-ASiNR. The peaks in the energy loss spectra for both systems represent the characteristics associated with the plasma resonance, which correspond to the trailing edges in the reflection spectra. These properties show that the different terminated atoms in 7-ASiNRs affect mainly the optical properties in the low energy range. Because of the rich optical properties, the 7-ASiNR could be a potential candidate for photoelectric nanodevice.