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

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 N Z -ZAlNNR-C( n ) with N Z = 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 N A -AAlNNR-C( n ) of arbitrary width N A , except N A -AAlNNR-C(1) and N A -AAlNNR-C( n = N A ) have a larger band gap, the band gap of the rest of the N A -AAlNNR-C( n ) are about 2.0 eV. Furthermore, the maximum band gap gradually decrease with the increase of the width N A . The C-chain substituting Al–N chain process is endothermic for both 7-ZAlNNR and 7-AAlNNR. [ABSTRACT FROM AUTHOR]