Tuning the transport properties of penta-graphene nanoribbons

Penta-graphene nanoribbons (PGNRs) exhibit unique semiconducting behavior in sawtooth edge configurations (SS-PGNRs). Doping is one of the most effective methods for tuning the transport properties of SS-PGNRs. However, the effects of doping concentration remain insufficiently studied. In this work, using both ordered and disordered doping, we systematically investigate the influence of doping sites, doping concentration and dopant elements on the transport characteristics of SS-PGNRs by combining density functional theory (DFT) with the non-equilibrium Green's function (NEGF). For ordered single-nitrogen doping where one nitrogen atom is introduced into an 18-atom unit cell of the SS-PGNR, substitutions at sp²-hybridized carbon sites significantly improve currents and induce pronounced negative differential resistance (NDR) effects. For ordered double-nitrogen doping where two nitrogen atoms are introduced into the same unit cell, these configurations further enhance both the current and the NDR strength, although they also raise the threshold voltage required to trigger the NDR effects. For disordered doping, N-15% yields the highest peak-to-valley ratio (PVR) of 2067, which has the best on/off performance. N-20% provides a lower PVR than N-15%, but with a larger current. Comparative analysis of N-, B-, and P-doping reveals that N-doping provides the best overall performance in terms of current, NDR strength, and PVR. This study provides theoretical guidance for the design of high-performance PGNR-based nano-electronic devices.