Thermoelectric and electronic properties of B-doped graphene nanoribbon

The effect of concentration and position of boron atoms as impurities in graphene nanoribbons have been studied through density functional theory (DFT) and the Landauer approach. For this purpose, we designed a graphene nanoribbon doped with three different concentrations of boron atoms and calculated the density of states (DOS), electronic current, and thermopower. The comparison between the DOS curve of the pure graphene and that of the boron-doped graphene shows that the presence of boron atoms as impurities in graphene has caused an energy gap near the Fermi energy. Moreover, the study of the I-V characteristics shows that not only the current quantization is established, but also the reduction in conductivity caused by doping with boron atoms can be observed; however, this reduction is not sensitive to the concentration of boron atoms. In addition, the changes of the Seebeck coefficient shows that in both pure and boron-doped graphene, the curve has a minimum value at the temperature of 10 K, which decreases to a lower value by increasing the concentration of boron atoms. Generally, the result of calculations shows that by increasing the boron concentration, not only the energy gap of graphene is changed, but also several changes appear in its thermoelectric properties that can be attributed to the impurity potential distribution. The results of this study can be effectively used for designing semiconductor electronic devices based on the graphene nanoribbon.