First-principles study on electronic and optical properties of Mg-N dual-acceptor codoped CuAlO2

Incorporation of impurities in CuAlO 2 provides an opportunities to modulate its electronic and optical properties, which can be exploited for the applications of optoelectronic devices. Among the various elements doped of CuAlO 2 , research on the codoping magnesium (Mg) with nitrogen (N) which may be a promising way for fabricating p-type CuAlO 2 is still limited. Here, the first-principles calculation based on density functional theory was used to investigate the electronic and optical properties of Mg-doped, N-doped and Mg–N codoped CuAlO 2 . Compared with the undoped CuAlO 2 , the lattice parameters a and c of the Mg–N codoped CuAlO 2 become larger and smaller, respectively. The acceptor level induced by 2 p state of N in N-doped CuAlO 2 is very deep. The undoped and Mg-doped CuAlO 2 has indirect band gap. Whether the deep acceptor level or the indirect band gap, it is unfavorable to p -type doping or light emission. Due to the hybridization of 3 p state of Mg and 2 p state of N on the top of the valence band, the Mg–N codoped CuAlO 2 not only has a direct band gap, but also has a shallower acceptor level (about 0.24 eV above the top of the valence band). The optical properties of CuAlO 2 changes obviously after Mg–N codoping in the area of low energy. These results suggest that the possibility of enhancing the hole concentration in CuAlO 2 by Mg–N dual-acceptor codoping which will be beneficial to the application of CuAlO 2 in optoelectronic devices.