Structural and electronic properties of a single C chain doped zigzag AlN nanoribbon

► The border states exist in Nz-ZAlNNR-C(n). ► Only Nz-ZAlNNR-C(1) has a direct band gap, the others have the indirect band gaps. ► Band gaps of Nz-ZAlNNR-C(1) and Nz-ZAlNNR-C(2) are 0.132 and 1 eV, respectively. ► Band gap of Nz-ZAlNNR-C(n) (n = Nz) decreases linearly with increasing Nz. ► Band gap of Nz-ZAlNNR-C(n) (Nz > 2) decreases with increasing n.