Effect of impurities and carrier concentration on conductivity of bilayer graphene double layer system in different dielectric environments

The electronic transport properties of the bilayer graphene double layer (BLGDL) system at T=0K using the Boltzmann transport equation are reported here. The conductivity of the BLGDL system has been calculated with varying parameters as relative carrier concentration (n(c)/n(CI)), short-range (point defect) and long-range (Coulomb charge) impurity concentration, relative dielectric constant (epsilon r) and interlayer distance (d). The maximum conductivity has been achieved in the absence of short-range impurity. The short-range impurity plays a non-trivial meaningful role in high dielectric and high carrier concentration regimes and limits the conductivity. For higher epsilon r and higher n(c)/n(CI) values, the nature of the conductivity curve turns out to be of a sublinear nature, while in all other cases, it shows a superlinear trend. Suitable selection of relative dielectric constants, relative carrier concentration and interlayer distance helps to improve the conductivity of the BLGDL system. If the dielectric constant of the spacer is higher than the substrate material, the thickness of the spacer material helps remarkably in enhancing conductivity. Moreover, a comparison of BLGDL with our previously reported MLG-MLG double layer graphene system (DLGS) confirms that higher conductivity is achieved in the case of BLG-BLG system compared to DLGS.