Regulating the band gaps of seven stacking patterns of bilayer hexagonal boron nitrides by doping carbon atoms in opposite sites

Abstract

The band gaps of seven stacking patterns of bilayer hexagonal boron nitrides(h-BNs) are regulated by changing the doping positions of carbon atoms using density functional theory calculations. The calculation results dwell on that the AA1 stacking pattern h-BN has the largest band gap among seven stacking patterns of h-BNs. The influences of five different doping positions of carbon atoms to the band gap of AA1 stacking pattern bilayer h-BN are investigated and the results shows that the opposite doping model has the largest band gap decline among five doping configurations under the same doping content. As for the other four doping models, the calculation results illustrate that the adjacent doping model is the most stable configuration, the remote doping configuration makes the planar construction of bilayer h-BN destroyed and the two cases of alternate doping configurations present metal properties. Therefore, the opposite doping model is the most valuable doping configuration. Bilayer h-BN transformed from insulating state to semiconductor state and the optical absorption coefficient of it shows that the absorption peak shifts to longer wavelength range after doping carbon atoms into opposite sites. Density of states and electron densities results indicate that the main reason of band gap decline is the charge transfer among atoms. This research should be helpful for designing band gaps of h-BN bilayers in nano- electronics applications.