Electronic state and momentum matrix of H-passivated silicon nanonets: A first-principles calculation

The poor light emission efficiency in silicon prevents its wide application in the field of optoelectronics. Tailoring silicon into direct band-gap semiconductor, will not only vigorously promote the development of silicon-based optoelectronic integrated circuits, but also make significant achievements in the field of solid-state light sources and solar cells. This article explores the nature of the electronic states of the direct band-gap H-passivated silicon nanonets and discusses the mechanism of the band-edge momentum matrix enhancement by means of first-principles calculation. A well corresponding relationship between the band-edge levels of bulk-like silicon and silicon nanonet is established. The first several conduction bands of silicon nanonets have the characteristic of folding energy levels, but the quantum confinement effect induces larger enhancement in momentum matrix elements than those of traditional silicon nanostructures. Two nano-fabrication techniques are proposed to produce the nanonet structure, as is expected to be widely applied in optoelectronic integrated circuits.