Despite the great promise of InSe for electronic and optoelectronic applications, Fröhlich interaction plays an important role in electrical transport due to the polar nature of it, which can become more significant in reduced dimensionality. Here, we report on how the dimensionality influences the strength and nature of the Fröhlich polaronic effect in InSe with the aid of plasmonic hot electrons injection. Polar optical phonons couple to hot electrons via the Fröhlich interaction in InSe and enable us to monitor them in conventional Raman measurements. We observed that the intensity of these phonon modes initially increases gradually with decreasing layer number and then drops drastically from 7 L to 6 L (transition from quasi-direct to indirect bandgap at room temperature). Additionally, a gradual decrease of intensity of the polar modes with further decreasing layer number is observed due to the increasing indirect bandgap nature of InSe suggesting reduced Fröhlich coupling below this thickness.

尽管 InSe 在电子和光电应用方面具有巨大的前景，但由于其极性性质，Fröhlich 相互作用在电传输中发挥着重要作用，这在降维时会变得更加重要。在这里，我们报告了在等离子体热电子注入的帮助下，维数如何影响 InSe 中 Fröhlich 极化子效应的强度和性质。极性光学声子通过 InSe 中的 Fröhlich 相互作用与热电子耦合，使我们能够在传统的拉曼测量中监测它们。我们观察到这些声子模式的强度最初随着层数的减少而逐渐增加，然后从 7 L 急剧下降到 6 L（在室温下从准直接带隙过渡到间接带隙）。此外，