All-dielectric thin films based on single silicon materials for angle-insensitive structural colors

Here we demonstrate a red structural color of a multilayer structure made of all silicon-based materials. By using amorphous silicon (a-Si) and silicon dioxide (SiO2) with a large difference in the refractive index, high reflection efficiency can be achieved with only a few layers. The anti-reflection unit composed of top silicon monoxide (SiO) and SiO2 layers can significantly reduce the reflection intensity of the non-target wavelengths to ensure that the device has good color saturation. The selective absorption of SiO and a-Si layers can further improve the color saturation. By reasonably controlling the thickness of the highly absorbing materials, the device has good angular insensitivity at an incident angle of 0 degrees-60 degrees. Furthermore, the angle-insensitive blue and yellow structural colors are also realized based on the all silicon design idea. This scheme is simple in structure and capable of efficient mass production. This method has enormous potential for diverse applications in display, colorful decoration, anti-counterfeiting, and so forth. (C) 2021 Optical Society of America