Enhanced Capacitance of Composite Anodic ZrO₂ Films Comprising High Permittivity Oxide Nanocrystals and Highly Resistive Amorphous Oxide Matrix

Abstract

Anodic oxide films with nanocrystalline tetragonal ZrO 2 precipitated in an amorphous oxide matrix were formed on Zr-Si and Zr-Al alloys and had significantly enhanced capacitance in comparison with those formed on zirconium metal. The capacitance enhancement was associated with the formation of a high-temperature stable tetragonal ZrO 2 phase with high relative permittivity as well as increased ionic resistivity, which reduces the thickness of anodic oxide films at a certain formation voltage. However, 2 there is a general empirical trend that single-phase materials with higher permittivity have lower ionic resistivity. This study presents a novel material design based on a nanocrystalline-amorphous composite anodic oxide film for capacitor applications.

Highly increased capacitance and thermal stability of anodic oxide films on oxygen-incorporated Zr-Ti alloy

“…The thickness of the anodic oxide film is 125 ± 3 nm, corresponding to the formation ratio of 2.50 ± 0.06 nm V -1 . This ratio on the Zr-24 at% Ti alloy is slightly smaller than that on Zr (2.70 nm V -1 ) [36]. The reduction of film thickness by the addition of Ti is consistent with a previous study [33].…”

“…However, the capacitance value became nearly twice that on Ta after heat treatment, while the tan δ value was as low as that on Ta. The increased capacitance of the anodic oxide film on the oxygen-incorporated Zr-Ti alloy after heat treatment in comparison with that on the as-deposited, oxygen-free alloy may be related to the preferential formation of t-ZrO 2 phase, which has much higher permittivity in comparison with m-ZrO 2 [36].…”

“…Further, when Al or Si was added to Zr, anodic oxide films of reduced thickness were formed in addition to the preferential formation of t-ZrO 2 , both contributing to the enhancing the capacitance [36,37,40,41]. The anodic oxide films formed on Zr-Al and Zr-Si alloys consisted of a mixture of t-ZrO 2 nanocrystalline phase and an amorphous matrix enriched in Al or Si species.…”

The Growth, Composition, and Functional Properties of Self‐Organized Nanostructured ZrO2‐Al2O3 Anodic Films for Advanced Dielectric Applications

“…The experimentally determined apparent permittivity of the PAA‐inbuilt films (ε = 11) is lower relative to anodic ZrO 2 (ε = 22) and larger relative to anodic Al 2 O 3 (ε = 9) reported in the literature. [ 47,48 ]…”

Mixed oxide growth on combinatorial aluminium–gadolinium alloys — a thermodynamic and first-principles approach

“…The dielectric constant of Gd 2 O 3 can be further used to modify the dielectric behaviour of aluminium-based alloys. The dielectric constant is one of the factors responsible for capacitance enhancement, and portable electronic devices have increased the demand for small-size electrolytic capacitors with high capacitance, low equivalent series resistance, and low leakage current [29,30]. Materials with high dielectric constants are also crucial in many areas of modern microelectronics for miniature supercapacitors, infrared detectors, radar absorbing coatings, and holographic devices.…”