A first-principles study of a single C-chain doped AlN nanoribbons

•We model C-chain doped AlN nanoribbons with zigzag edges and armchair edges.•Variation behaviors in band gap are exhibited by doping C-chain in (Z)AAlNNR.•The C-chain can change the band gap of 7-ZAlNNR from direct to indirect.•The C-chain substituting Al–N chain process is endothermic.

Under the generalized gradient approximation (GGA), the structural and electronic properties are studied for both zigzag (ZAlNNRs) and armchair (AAlNNRs) AlN nanoribbons terminated with H atoms at both edges by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The results show that the Al–N, Al–C and Al–H bonds are ionic bonds while the C–C and C–H bonds are typical covalent bonds, and the N–C and N–H bonds have a degree covalent character. The systems of both perfect 7-ZAlNNR and perfect 7-AAlNNR with a single C-chain doped are still nonmagnetic semiconductors, and the C-chain reduces the band gap. The C-chain can change the band gap of 7-ZAlNNR from direct to indirect independent of the position of the C-chain, which is important in the practical application as light emitting devices. For NZ-ZAlNNR-C(n) with NZ = 3, 5, 6, 10, the band gap decrease successively for C-chain position n from 2 to 3, 5, 6, 7 and 10, respectively. For NA-AAlNNR-C(n) of arbitrary width NA, except NA-AAlNNR-C(1) and NA-AAlNNR-C(n = NA) have a larger band gap, the band gap of the rest of the NA-AAlNNR-C(n) are about 2.0 eV. Furthermore, the maximum band gap gradually decrease with the increase of the width NA. The C-chain substituting Al–N chain process is endothermic for both 7-ZAlNNR and 7-AAlNNR.