Title / Titre :
BZW Results for the Band Gaps of Bulk, Nanoscale, and Novel Semiconductors
Author(s) / Auteur(s) :
Diola Bagayoko, G. L. Zhao, Saleem Hasan, Troy D. William*, Yixin Luo*, and Lashounda Torrence*
Address / Adresse :
Department of Physics
Southern University and A&M College
Baton Rouge, Louisiana 70813
Key words / Mots clés :
energy levels, band gaps, electronic properties, semiconductors, prediction
Abstract / Résumé : From the advent of quantum theory to very recently, calculated band gaps of semiconductors and of insulators grossly disagreed with experiment. Specifically, band gaps calculated with local density approximation (LDA) potentials were 30% to 50% smaller than experimental values. We review the recent resolution of this serious discrepancy, dubbed the band gap catastrophe, with the Bagayoko, Zhao, and Williams (BZW) method. In particular, we present our correctly calculated band gaps, optical and related properties of semiconductors that are in excellent agreement with experiment, even though they are obtained with LDA potentials. Materials discussed include silicon (Si), diamond (C), germanium (Ge), ZnO, GaN, BaTiO3, ZnSe, 3C-SiC, c-Si3N4, AlN, and selected carbon nanotubes. The predictive capability of the BZW method, for the electronic and related properties of semiconductors, portends serious implications for device design and fabrication processes. In particular, BZW calculations can guide device fabrication processes due to their provision of correct band gaps for semiconductors. The prevalence and non-negligible nature of quantum properties of nanoscale materials further underscore the importance of the method. This ab-initio method is applicable not only to bulk and nanoscale materials, but also for the description of atoms and molecules and the prediction of novel materials that may be inorganic or biological. This work was funded in part by NASA (Cooperative Agreement No. NCC13-00010), the National Science Foundation and the Louisiana Board of Regents (Award No. HRD 000272), and the Department of the Navy, Office of Naval Research (ONR, Grant No. N00014-98-1-0748). The ONR funding is through the Timbuktu Academy. * Former graduate students of Dr. Bagayoko and of Dr. Zhao.