First-principles investigation of electronic structure and optical properties in N-F codoped ZnO with wurtzite structureJ. Wen, C. Y. Zuo, M. Xu, C. Zhong and K. QiEur. Phys. J. B, 80 1 (2011) 25-30DOI: https://doi.org/10.1140/epjb/e2011-10295-y