Nonvolatile optical phase shift in ferroelectric hafnium zirconium oxide.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38724501.
- Also identified by DOI 10.1038/s41467-024-47893-2 and PMC identifier 11082191.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
A nonvolatile optical phase shifter is a critical component for enabling the fabrication of programmable photonic integrated circuits on a Si photonics platform, facilitating communication, computing, and sensing. Although ferroelectric materials such as BaTiO<sub>3</sub> offer nonvolatile optical phase shift capabilities, their compatibility with complementary metal-oxide-semiconductor fabs is limited. Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> is an emerging ferroelectric material, which exhibits complementary metal-oxide-semiconductor compatibility. Although extensively studied for ferroelectric transistors and memories, its application to photonics remains relatively unexplored. Here, we show the optical phase shift induced by ferroelectric Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub>. We observed a negative change in refractive index at a 1.55 μm wavelength in a pristine device regardless of the direction of the applied electric field. The nonvolatile phase shift was only observed once in a pristine device. This non-reversible phase shift can be attributed to the spontaneous polarization within the Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> film along the external electric field.