Tuning the electronic properties of armchair carbon nanoribbons by a selective boron doping

Abstract

Armchair carbon nanoribbons (ACNRs) substitutionally doped with boron atoms are investigated in the framework of first-principles density functional theory. Different boron-boron arrangements and concentrations are considered in order to simulate possible aggregation patterns, their structural stability and electronic behavior are determined as a function of ribbon size. In agreement with previous studies, our results show that the dopant atoms have in general a preference for edge sites, but specific effects appear as a function of concentration that importantly modify the properties of the ribbons compared to the pristine case. Interesting tendencies are discovered as a function of dopant concentration that significantly affect the electronic properties of the ribbons. We have found that BC(3) island formation and edge doping are the most important factors for the structural stabilization of the ribbons with high boron concentration (>7%) whereas for the cases of low boron concentrations (<5%) the structural stabilities are similar. For all the doped cases, we have found that the BC(3) island patterns give rise to highly localized B states on top of the Fermi level, resulting in semiconducting behavior. On the other hand, when the average distance between the B atoms increases beyond island stoichiometry, the localization of their states is reduced and the ribbons may become metallic due to a band crossing caused by the lowering of the Fermi level resulting from the positive charge doping. Thus, tuning the dopant interaction would be an appropriate way to tailor the electronic properties of the ribbons in a convenient manner in view of potential technological applications.

Dibenzothiophene adsorption at boron doped carbon nanoribbons studied within density functional theory

“…The B doping slightly reduces the cohesive energy compared to the pristine ACNRs. As shown elsewhere, 26 this reduction becomes less important when the system size increases. In particular, the energy reduces while the island is nearby the ribbon edge indicating that the formation of the BC 3 island 47 and the substitution on the edges 48,49 are keys to ACNRs stability routes.…”

“…The ACNRs and B-ACNRs electronic properties have been previously studied in our group 26 by using a similar methodology as in the present research. It was found that B-ACNRs with BC 3 island conformations are more stable than random B arrangements.…”

“…By following the usual convention, 26 the size of the ACNRs is denoted as M Â N, where M is the number of rows along the transverse (x) direction, and N represents the number of rows along the periodic (z) direction as shown in Fig. 1.…”

“…As a result, a grid of 1 Â 15 Â 1 points the Monkhorst-Pack and a plane-wave cutoff energy of 500 eV represents a good compromise between precision and computing time for the optimization of the electronic density at each relaxation step. As the ACNRs do not show significant magnetization effects, 23,26 whole analyses performed do not include spin polarization solutions.…”

Ab initio study of the interactions between boron and nitrogen dopants in graphene

“…2,7 The structural and electronic characteristics of B-and N-doped graphene sheets and GNRs have been studied both experimentally [22][23][24][34][35][36][37] and theoretically. 14,19,28,[38][39][40][41][42][43] However, the interactions between B and N impurities in graphene have not been investigated in detail. Understanding these interactions is important for the development of an accurate theoretical model of substitutionally doped graphene and GNRs.…”