Vivid, full-color aluminum plasmonic pixels

Aluminum is abundant, low in cost, compatible with complementary metal-oxide semiconductor manufacturing methods, and capable of supporting tunable plasmon resonance structures that span the entire visible spectrum. However, the use of Al for color displays has been limited by its intrinsically broad spectral features. Here we show that vivid, highly polarized, and broadly tunable color pixels can be produced from periodic patterns of oriented Al nanorods. Whereas the nanorod longitudinal plasmon resonance is largely responsible for pixel color, far-field diffractive coupling is used to narrow the plasmon linewidth, enabling monochromatic coloration and significantly enhancing the far-field scattering intensity of the individual nanorod elements. The bright coloration can be observed with p-polarized white light excitation, consistent with the use of this approach in display devices. The resulting color pixels are constructed with a simple design, are compatible with scalable fabrication methods, and provide contrast ratios exceeding 100:1.