@article{freitas_moore_1998,  title={Optical Studies of Undoped and Doped Wide Bandgap Carbide and Nitride Semiconductors},  volume={28},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97331998000100002},  DOI={10.1590/S0103-97331998000100002},  number={1},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Freitas, J.A. and Moore, W.J.},  year={1998},  month={Mar},  pages={12–18} }