Brilliant and tunable color of carbon-coated thin anodic aluminum oxide films

When a thin anodic aluminum oxide (AAO) film on an Al substrate is uniformly coated with carbon by chemical vapor deposition, the saturation of interference color is substantially enhanced and, as a result, the coated AAO film exhibits a brilliant color. Such remarkable saturation enhancement is predominantly due to the carbon deposited on the inner walls of nanochannels of the AAO film, which efficiently screens the reflected light from AAO–Al interface. The brilliant carbon-coated AAO film is useful for weather-resistant decorative purposes and holds promise as an effective broadband optical limiter for nanosecond laser pulse.