Reversible Thermally Driven Phase Change of Layered In₂Se₃ for Integrated Photonics

Two-dimensional In2Se3, an unconventionalphase-change material, has drawn considerable attention for polymorphicphase transitions and electronic device applications. However, itsreversible thermally driven phase transitions and potential use inphotonic devices have yet to be explored. In this study, we observethe thermally driven reversible phase transitions between & alpha;and & beta;& PRIME; phases with the assistance of local strain fromsurface wrinkles and ripples, as well as reversible phase changeswithin the & beta; phase family. These transitions lead to changesin the refractive index and other optoelectronic properties with minimaloptical loss at telecommunication bands, which are crucial in integratedphotonic applications such as postfabrication phase trimming. Additionally,multilayer & beta;& PRIME;-In2Se3 working asa transparent microheater proves to be a viable option for efficientthermo-optic modulation. This prototype design for layered In2Se3 offers immense potential for integrated photonicsand paves the way for multilevel, nonvolatile optical memory applications.