  Penta-graphene is a quasi-two-dimensional carbon allotrope consisting of a
pentagonal lattice in which both sp2 and sp3-like carbons are present. Unlike
graphene, penta-graphene exhibits a non-zero bandgap, which opens the
possibility of its use in optoelectronic applications. However, as the observed
bandgap is large, gap tuning strategies such as doping are required. In this
work, density functional theory calculations are used to determine the effects
of the different number of line defects of substitutional nitrogen or silicon
atoms on the penta-graphene electronic behavior. Our results show that this
doping can induce semiconductor, semimetallic, or metallic behavior depending
on the doping atom and targeted hybridization (sp2 or $sp3-like carbons). In
particular, we observed that nitrogen doping of sp2-like carbons atoms can
produce a bandgap modulation between semimetallic and semiconductor behavior.
These results show that engineering line defects can be an effective way to
tune penta-graphene electronic behavior.
