Controlled non-volatile modulation of optical dispersion in monolayer tungsten disulfide via ferroelectric polarization patterning

TL;DR

This paper demonstrates nonvolatile control of optical dispersion in monolayer tungsten disulfide using ferroelectric polarization patterning, enabling energy-efficient, reconfigurable photonic devices without continuous power consumption.

Contribution

It introduces a method to achieve nonvolatile optical modulation in 2D materials via ferroelectric domains, eliminating the need for continuous power and enabling new device functionalities.

Findings

Significant modulation of refractive index and excitonic energy in ML WS2.

Development of an asymmetric screening model for ferroelectric-induced effects.

Creation of a gate-free lateral p-n homojunction with high rectification ratio.

Abstract

The manipulation of optical properties, including reflection, refraction, polarization, phase, and frequency, has long been central to advancing photonic and optoelectronic technologies. However, existing electro-optical approaches rely on volatile mechanisms that require continuous power consumption. Here, we demonstrate strong, nonvolatile modulation of optical dispersion in monolayer tungsten disulfide (ML WS2) using patterned ferroelectric domains in aluminum scandium nitride (AlScN). By locally poling ferroelectric domains into opposite states, we achieve substantial manipulation of the complex refractive index (Delta n > 0.7, Delta k > 0.4) and excitonic energy shifts (~50 meV) in ML WS2, comparable to previous gate-tuning approaches while eliminating continuous power consumption. We introduce an asymmetric screening model that reveals how ferroelectric polarization induces carrier-density-dependent Coulomb screening, leading to distinct excitonic behaviors between electron- and hole-doped regions. Furthermore, we demonstrate a gate-free lateral p-n homojunction with a rectification ratio of 6e10^3, formed through spatial carrier redistribution. These findings establish ferroelectric/2D heterostructures as a powerful platform for nonvolatile optical dispersion engineering, enabling energy-efficient, reconfigurable photonic and optoelectronic devices.