Plasmonic hot electron induced layer dependent anomalous Fröhlich interaction in InSe

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