Electrochemical
Properties and Applications of Nanocrystalline, Microcrystalline,
and Epitaxial Cubic Silicon Carbide Films
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Abstract
Microstructures of the materials
(e.g., crystallinitiy, defects, and composition, etc.) determine their
properties, which eventually lead to their diverse applications. In
this contribution, the properties, especially the electrochemical
properties, of cubic silicon carbide (3C-SiC) films have been engineered
by controlling their microstructures. By manipulating the deposition
conditions, nanocrystalline, microcrystalline and epitaxial (001)
3C-SiC films are obtained with varied properties. The epitaxial 3C-SiC
film presents the lowest double-layer capacitance and the highest
reversibility of redox probes, because of its perfect (001) orientation
and high phase purity. The highest double-layer capacitance and the
lowest reversibility of redox probes have been realized on the nanocrystalline
3C-SiC film. Those are ascribed to its high amount of grain boundaries,
amorphous phases and large diversity in its crystal size. Based on
their diverse properties, the electrochemical performances of 3C-SiC
films are evaluated in two kinds of potential applications, namely
an electrochemical capacitor using a nanocrystalline film and an electrochemical
dopamine sensor using the epitaxial 3C-SiC film. The nanocrystalline
3C-SiC film shows not only a high double layer capacitance (43–70
μF/cm<sup>2</sup>) but also a long-term stability of its capacitance.
The epitaxial 3C-SiC film shows a low detection limit toward dopamine,
which is one to 2 orders of magnitude lower than its normal concentration
in tissue. Therefore, 3C-SiC film is a novel but designable material
for different emerging electrochemical applications such as energy
storage, biomedical/chemical sensors, environmental pollutant detectors,
and so on