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arXiv · 1904.00390

InSe as a case between 3D and 2D layered crystals for excitons

W. Desrat·T. V. Shubina·M. Moret·A. Tiberj·O. Briot·B. Gil
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Abstract

We demonstrate the successive appearance of the exciton, biexciton, and P band of the exciton-exciton scattering with increasing excitation power in the photoluminescence of indium selenide layered crystals. The strict energy and momentum conservation rules of the P band are used to reexamine the exciton binding energy. The new value $\geq 20$ meV is markedly higher than the currently accepted 14 meV, being however well consistent with the robustness of excitons up to room temperature. A peak controlled by the Sommerfeld factor is found near the bandgap ($\sim 1.36$ eV), which puts the question on the pure three-dimensional character of the exciton in InSe, which has been assumed up to now. Our findings are of paramount importance for the successful application of InSe in nanophotonics.

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W. Desrat, T. V. Shubina, M. Moret, A. Tiberj, O. Briot, B. Gil. 2019-03-31. InSe as a case between 3D and 2D layered crystals for excitons. https://arxiv.org/abs/1904.00390

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