Anomalous transport properties in boron and phosphorus co-doped armchair graphene nanoribbons.

Multi-element doping of graphene could potentially provide functionalities that are not available in the single-element doping approach, but it has not been actively studied so far. Carrying out first-principles calculations, we study the structural, electronic, and transport properties of B-P edge-co-doped armchair graphene nanoribbons (aGNRs). We find that the B, P-complex edge-doped aGNRs exhibit an n-type transport behavior, which is counterintuitive considering the p-type and bipolar characters of the corresponding B- and P-doped aGNRs, respectively. Moreover, we show that the n-type property of B, P co-doped aGNRs is superior to that of representative N-doped aGNRs in terms of preserving the valence band edge conductance spectrum. Analyzing the mechanisms, we demonstrate that the structural distortion rather than chemical valence induces the anomalous donor character of B, P co-doped aGNRs. We thus propose a systematic modification of GNR atomic structures via co-doping as a novel approach to control charge transport characteristics of GNRs.