Wavelength-dependent anisotropic light-matter interaction in 2D ferroelectric In2Se3

TL;DR

This paper explores how the anisotropic light-matter interactions in 2D ferroelectric In2Se3 depend on polarization and excitation energy, revealing potential for polarization-sensitive optoelectronic devices.

Contribution

It provides experimental and theoretical insights into the polarization-dependent optical anisotropy in 2D In2Se3, highlighting tunable photo-response for advanced applications.

Findings

Light-matter interactions depend on crystallographic orientation and excitation energy.

The material exhibits significant optical anisotropy driven by electron-photon and electron-phonon interactions.

The anisotropic photo-response can be tuned by light polarization and wavelength.

Abstract

The anisotropic light-matter interactions in 2D materials have garnered significant attention for their potential to develop futuristic polarization-based optoelectronic devices, such as photodetectors and photo-actuators. In this study, we investigate the polarization-dependent interactions in ferroelectric 3R alpha-In2Se3 using Angle-Resolved Polarized Raman Spectroscopy (ARPRS) with different excitation lasers. Our experimental findings supported by complementary Density Functional Theory calculations demonstrate that the light-matter interactions depend not only on the crystallographic orientation but also on the excitation energy. Scanning transmission electron microscopy (STEM) confirms the highly anisotropic 3R crystal structure of alpha-In2Se3. This anisotropy in crystal structure facilitates significant optical anisotropy, driven by a complex interplay of electron-photon and electron-phonon interactions, which is reflected in the complex nature of the Raman tensor elements. These anisotropy interactions extend to the materials electrical response under light illumination. Remarkably, the anisotropic photo-response can be tuned by both polarization and wavelength of the incident light, making In2Se3 a promising material for advanced polarization-sensitive photodetection applications.