pubs.acs.org/NanoLett
Tuning the Color of Silicon Nanostructures Linyou Cao, Pengyu Fan, Edward S. Barnard, Ana M. Brown, and Mark L. Brongersma* Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 ABSTRACT Empowering silicon (Si) with optical functions constitutes a very important challenge in photonics. The scalable fabrication capabilities for this earth-abundant, environmentally friendly material are unmatched in sophistication and can be unleashed to realize a plethora of high-performance photonic functionalities that find application in information, bio-, display, camouflage, ornamental, and energy technologies. Nanofashioning represents a general strategy to turn Si into a useful optical material and Si structures have already been engineered to enable light emission, optical cloaking, waveguiding, nonlinear optics, enhanced light absorption, and sensing. Here, we demonstrate that a wide spectrum of colors can be generated by harnessing the strong resonant light scattering properties of Si nanostructures under white light illumination. The ability to engineer such colors in a predetermined fashion through a choice of the structure size, dielectric environment, and illumination conditions opens up entirely new applications of Si and puts this material in a new light. KEYWORDS Silicon, nanophotonics, antenna, Mie resonance, structural color, sensors
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ilicon has dominated the microelectronics industry for decades, and its impressive performance as an electronic material is undisputable. Its use as an optical material is also rapidly gaining popularity, but the development of Si-based optical technologies is hampered by the inability of Si to efficiently emit light.1 Si is a poor light emitter because of its indirect bandgap, which precludes photon emission without the involvement of a phonon. Such processes are slow and excited electron-hole pairs tend to recombine via faster nonradiative pathways. The use of quantum size effects in very small (
