Shubina T V, Desrat W, Moret M, Tiberj A, Briot O, Davydov V Yu, Platonov A V, Semina M A, Gil B
Ioffe Institute, 26 Politekhnicheskaya, St Petersburg, 194021, Russia.
Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, FR-34095, France.
Nat Commun. 2019 Aug 2;10(1):3479. doi: 10.1038/s41467-019-11487-0.
InSe is a promising material in many aspects where the role of excitons is decisive. Here we report the sequential appearance in its luminescence of the exciton, the biexciton, and the P-band of the exciton-exciton scattering while the excitation power increases. The strict energy and momentum conservation rules of the P-band are used to reexamine the exciton binding energy. The new value ≥20 meV is markedly higher than the currently accepted one (14 meV), being however well consistent with the robustness of the excitons up to room temperature. A peak controlled by the Sommerfeld factor is found near the bandgap (~1.36 eV). Our findings supported by theoretical calculations taking into account the anisotropic material parameters question the pure three-dimensional character of the exciton in InSe, assumed up to now. The refined character and parameters of the exciton are of paramount importance for the successful application of InSe in nanophotonics.
在许多激子起决定性作用的方面，硒化铟（InSe）都是一种很有前景的材料。在此我们报告，随着激发功率增加，其发光中依次出现激子、双激子以及激子 - 激子散射的P带。利用P带严格的能量和动量守恒规则重新审视激子结合能。新值≥20 meV明显高于目前公认的值（14 meV），不过这与激子在室温下的稳健性非常一致。在带隙（~1.36 eV）附近发现了一个由索末菲因子控制的峰。考虑到各向异性材料参数的理论计算支持了我们的发现，这对迄今为止所假设的InSe中激子的纯三维特性提出了质疑。激子的精细特性和参数对于InSe在纳米光子学中的成功应用至关重要。
