Engineering Electro-Optic BaTiO3 Nanocrystals via Efficient Doping

Sasa Wang, Tong Zhu, Randy Sabatini, Amin Morteza Najarian, Muhammad Imran, Ruyan Zhao, Pan Xia, Lewei Zeng, Sjoerd Hoogland, Dwight S. Seferos, Edward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Electro-optic (EO) modulators provide electrical-to-optical signal conversion relevant to optical communications. Barium titanate (BaTiO3) is a promising material system for EO modulation in light of its optical ultrafast nonlinearity, low optical loss, and high refractive index. To enhance further its spontaneous polarization, BaTiO3 can be doped at the Ba and Ti sites; however, doping is often accompanied by ion migration, which diminishes EO performance. Here, donor–acceptor doping and its effect on EO efficiency are investigated, finding that La-doped BaTiO3 achieves an EO coefficient of 42 pm V−1 at 1 kHz, fully twice that of the pristine specimen; however, it is also observed that, with this single-element doping, the EO response falls off rapidly with frequency. From impedance spectroscopy, it is found that frequency-dependent EO is correlated with ion migration. Density functional theory calculations predict that the ion-migration barrier decreases with La3+ doping but can be recovered with further Mn2+ doping, a finding that prompts to prevent ion migration by incorporating Mn2+ into the Ti-site to compensate for the charge imbalance.

Original languageEnglish (US)
Article number2207261
JournalAdvanced Materials
Volume34
Issue number47
DOIs
StatePublished - Nov 24 2022

Keywords

  • barium titanate
  • doping
  • electro-optic modulators
  • ion migration
  • nanoparticles

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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