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Exploring Direct to Indirect Bandgap Transition in Silicon Nanowires: Size Effect

Research paper by Lihong Shi, Gang Zhang

Indexed on: 22 Jun '16Published on: 22 Jun '16Published in: Journal of Electronic Materials



Abstract

We have investigated the electronic band structure of [110] 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 [110] 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.