Mr. Xi Lin - M.Sc. Candidate
13/10/2024
ZOOM
14:30 - Jerusalem time / 19:30 - Beijing time
Polymeric dielectrics are vital in energy storage systems and electronic components, with applications in technologies like electric vehicles. Their energy density depends on the electric field strength and polarization, but enhancing breakdown strength while maintaining a stable dielectric constant remains a challenge. Recent studies on inorganic coatings for polymer dielectrics show promise, though the mechanisms are not fully understood.
This study investigates aluminum oxide (Al₂O₃) and titanium oxide (TiOx) films deposited on 5-micrometer polyetherimide (PEI) polymers using atomic layer deposition (ALD). Film nanostructures and defect states were analyzed using techniques like X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (sXAS). The dielectric breakdown strength and leakage current were also evaluated. Results showed that defect states in ultra-thin aluminum oxide films act as deep charge traps, enhancing charge capture at the organic-inorganic interface and limiting carrier migration. A model incorporating trap and barrier layers was proposed to enhance dielectric strength. Additionally, titanium oxide-aluminum oxide heterostructures demonstrated superior breakdown strength compared to singleoxide-layer coatings, highlighting the potential of ALD for advanced high-energy-density capacitors.