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arXiv · 2308.10730

Band gap reduction in highly-strained silicon beams predicted by first-principles theory and validated using photoluminescence spectroscopy

Nicolas Roisin·Marie-Stéphane Colla·Romain Scaffidi·Thomas Pardoen·Denis Flandre·Jean-Pierre Raskin
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Abstract

A theoretical study of the band gap reduction under tensile stress is performed and validated through experimental measurements. First-principles calculations based on density functional theory (DFT) are performed for uniaxial stress applied in the [001], [110] and [111] directions. The calculated band gap reductions are equal to 126, 240 and 100 meV at 2$\%$ strain, respectively. Photoluminescence spectroscopy experiments are performed by deformation applied in the [110] direction. Microfabricated specimens have been deformed using an on-chip tensile technique up to ~1$\%$ as confirmed by back-scattering Raman spectroscopy. A fitting correction based on the band gap fluctuation model has been used to eliminate the specimen interference signal and retrieve reliable values. Very good agreement is observed between first-principles theory and experimental results with a band gap reduction of, respectively, 93 and 91 meV when the silicon beam is deformed by 0.95$\%$ along the [110] direction.

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Nicolas Roisin, Marie-Stéphane Colla, Romain Scaffidi, Thomas Pardoen, Denis Flandre, Jean-Pierre Raskin. 2023-08-21. Band gap reduction in highly-strained silicon beams predicted by first-principles theory and validated using photoluminescence spectroscopy. https://arxiv.org/abs/2308.10730

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