​RESEARCH FACILITIES
1. Materials Synthesis: Pulsed laser deposition, RF Magnetron sputtering etc.
2. Microstructure Characterization: (S)TEM/SAED/EDS/EELS, XRD/phi/pole figure/RSM, SEM/EDS, AFM, Cs-corrected (S)TEM, in situ TEM heating, in situ nanoindentation/bias in TEM, 3D STEM tomography, DPC, iDPC etc.
3. Optical Characterization: UV-vis-NIR spectrometer, Spectroscopic ellipsometry, Raman spectroscopy, FTIR etc.
4. Physical Property Measurement: PFM, Electric probe station, PPMS, MPMS etc.
5. Simulation: COMSOL Multiphysics.
6. Data Analysis and Visualization: Office suite, Origin, 3dMax, Adobe illustrator, Photoshop, Lightroom, MATLAB, Python etc.
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RESEARCH HIGHLIGHTS
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Significance: The paper reviews the main approaches of tuning the dielectric permittivity (ε) in self-assembled metal–dielectric vertically aligned nanocomposite (VAN) hybrid thin films. By varying the key parameters such as metal density and geometry, film strain states and background pressure, or seeking alternative metal-free and complex structure designs, highly tunable permittivity as well as exotic physical properties can be realized, presenting enormous potential applications in the filed of electronics and nanophotonic devices.
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Reference:
Di Zhang, Haiyan Wang. Advanced Photonics Research. (invited review) 2021, 2(5): 2000174.
Work 2: Tunable Optical Properties in Self-assembled Oxide-Metal Hybrid Film via Au-Phase Geometry Control
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Significance: This project developed a new type of oxide-metal vertically aligned nanocomposite film with distinct optical and ferroelectric properties. By varying the film thickness, the Au geometry within in films transfers from “nanopillars” to “nanodisks”. Different Au aspect ratio and free electron density lead to the shift of plasmon resonance peak and hyperbolic dispersion.
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Reference:
Di Zhang et al. Adv. Opt. Mater. 2020, 8(4): 1901359.
Work 4: Thermally Stable Au-BaTiO3 Nanoscale Hybrid Metamaterial for High Temperature Plasmonic Applications
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Significance: This project reveals the excellent thermal stability of the self-assembled Au-BaTiO3 hybrid thin films. From ex situ annealing followed by XRD, TEM and optical property measurements as well as the in situ heating study in TEM, all demonstrate the thermal robustness of the film, showing great potential in high temperature plasmonic device applications.
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Reference:
Di Zhang et al. ACS Applied Nano Materials. 2020, 3(2): 1431-1437.
Work 3: Design of 3D Oxide-Metal Hybrid Metamaterial for Tailorable Light-Matter Interactions
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Significance: This project ​designed a 3D multilayered BaTiO3-Au hybrid film with various dielectric interlayers to form a “bamboo-like” structure. Through strain engineering, the diameter and distribution density of Au nanopillars are effectively tailored, leading to highly tunable optical properties, with typical ferroelectric behavior and robust characteristic at high temperatures
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Reference:
Di Zhang et al. Adv. Opt. Mater. 2021, 9(1): 2001154.
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Significance: This work emonstrates a templated growth method of plasmonic alloyed-based BaTiO3-Au0.4Ag0.6 hybrid film with ordered “nano-domino-like” microstructure. The alloyed hybrid film exhibits much broader tunability of localized plasmon resonance and hyperbolic dispersion in UV-Vis-NIR regime with low-loss and thermal robustness characteristics.
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Reference:
Di Zhang et al. ACS Applied Materials & Interfaces. 2021, 13(4): 5390-5398.
COLLABORATIONS
Prof. Judith MacManus-Driscoll (University of Cambridge)
Prof. Quanxi Jia (University of Buffalo)
Prof. Hao Yang (Nanjing University of Aeronautics and Astronautics, China)
Prof. Judy Wu (University of Kansas)
Prof. Peide Ye (Purdue University)
Prof. Jianguo Mei (Purdue University)
Prof. Jiming Bao (University of Houston)
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