Colossal Dielectric Constant of Nanocrystalline/Amorphous Homo-Composite BaTiO3 Films Deposited via Pulsed Laser Deposition Technique

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2024-10, Vol.14 (20), p.1677
• Main Authors: Kondo, Shinya, Murakami, Taichi, Pichon, Loick, Leblanc-Lavoie, Joël, Teranishi, Takashi, Kishimoto, Akira, El Khakani, My Ali
• Format: Article
• Language: English
• Subjects: Barium titanates; BaTiO3; Carrier transport; colossal dielectric constant; Communication; Crystallization; Current carriers; Dielectric constant; Dielectric loss; Dielectric properties; Electrodes; Grain size; High resolution electron microscopy; Lasers; Morphology; nanocrystalline/amorphous homo-composite; Nanocrystals; Pulsed laser deposition; Pulsed lasers; Scanning electron microscopy; Spectrum analysis; Substrates; Temperature; thin film; Thin films; Transmission electron microscopy
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano14201677

We report the pulsed laser deposition (PLD) of nanocrystalline/amorphous homo-composite BaTiO3 (BTO) films exhibiting an unprecedented combination of a colossal dielectric constant (εr) and extremely low dielectric loss (tan δ). By varying the substrate deposition temperature (Td) over a wide range (300–800 °C), we identified Td = 550 °C as the optimal temperature for growing BTO films with an εr as high as ~3060 and a tan δ as low as 0.04 (at 20 kHz). High-resolution transmission electron microscopy revealed that the PLD-BTO films consist of BTO nanocrystals (~20–30 nm size) embedded within an otherwise amorphous BTO matrix. The impressive dielectric behavior is attributed to the combination of highly crystallized small BTO nanograins, which amplify interfacial polarization, and the surrounding amorphous matrix, which effectively isolates the nanograins from charge carrier transport. Our findings could facilitate the development of next-generation integrated dielectric devices.