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Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain
Published on: March 27, 2018
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Engineering Refractive Index Contrast in Thin Film Barium Titanate-on-Insulator
Yu Cao1, Haidong Liang2, Hong-Lin Lin1
1Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
Nano Letters
|August 2, 2023
Summary
Researchers developed three etch-free methods for barium titanate-on-insulator waveguides, overcoming limitations of traditional etching. Molybdenum diffusion achieved a significant refractive index change, enabling advanced on-chip optical devices.
Area of Science:
- Materials Science
- Photonics
- Nanotechnology
Background:
- Barium titanate-on-insulator (BTO) exhibits strong electro-optic properties and excellent optical confinement.
- Fabricating waveguide devices requires creating a higher refractive index region for mode confinement.
- Traditional dry etching methods for BTO result in surface roughness, limiting ridge depth and device performance.
Purpose of the Study:
- To explore etch-free techniques for creating refractive index contrast in BTO.
- To overcome the limitations associated with physical etching of BTO waveguides.
- To enable the fabrication of advanced on-chip optical devices using BTO.
Main Methods:
- Investigated three etch-free methods: metal diffusion, proton beam irradiation, and crystallinity control.
- Utilized molybdenum diffusion to alter the refractive index of BTO.
- Analyzed the resulting refractive index changes and their impact on optical confinement.
Main Results:
- Successfully demonstrated three viable etch-free methods for index contrast in BTO.
- Molybdenum-diffused BTO showed a substantial refractive index change of up to 0.17.
- These methods avoid the sidewall and surface roughness issues inherent in dry etching.
Conclusions:
- Etch-free methods offer a promising alternative for fabricating BTO-on-insulator optical waveguides.
- The demonstrated techniques, particularly metal diffusion, facilitate the creation of high-performance on-chip photonic devices.
- Further development of these methods can lead to novel integrated BTO optical devices.
