Indexed on: 22 Jun '16Published on: 22 Jun '16Published in: Journal of Electronic Materials
We have investigated the electronic band structure of  silicon nanowires (SiNWs) using first-principles calculations. We find that, in the ultrathin diameter regime, SiNWs have a direct bandgap, but the energy difference between the indirect and direct fundamental bandgaps decreases as the nanowire diameter increases. This indicates that larger  SiNWs could have an indirect bandgap. Fundamentally, a series of quantitative direct–indirect bandgap transitional diameters are obtained for different cross-sectional geometries, with the largest values for SiNWs with triangular cross section.