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Updated: Oct 12, 2025

Developing High Performance GaP/Si Heterojunction Solar Cells
Published on: November 16, 2018
Near-infrared non-degenerate two-photon absorption coefficients of bulk GaAs and Si
Abstract:
We investigate the non-degenerate two-photon absorption coefficient β(ω1, ω2) as a function of the non-degeneracy parameter ω1/ω2 for bulk GaAs and Si at a constant transition energy ℏ ω 1+ℏ ω 2=1.57eV. In both materials, the two-photon absorption strength increases with increasing ω1/ω2 regardless of the direct and indirect character of the bandgap. The GaAs measurement data agrees well with corresponding theoretical predictions for direct semiconductors. The Si data reveals similar trends albeit with smaller overall absorption strength. In addition, different crystallographic orientations and polarization configurations are analyzed.
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