Lithography-Free Nanofilm Color Filters Composed of CMOS-Compatible Materials

Nanostructures with the ability to efficiently generate colors in visible range attract lots of attention. Current plasmonic materials-based techniques always require complicated lithographic processes, which are expensive and severely limiting the production throughput. In this letter, we experimentally demonstrate a large-area silicon-based multilayer structure for color filtering. The designed lithography-free nanofilm color filters possess high transmission (>70%) and wide-angle tolerance (up to ±30°) for both TE and TM polarizations. Our approach, featuring excellent performance together with CMOS compatible materials, steps forward towards practical applications such as image sensors and display devices.