Semiconductor quantum-dot photonic crystals

Summary form only given. Here we show how to use self-organization to make three-dimensional semiconductor photonic crystals operating at optical wavelengths. Our approach combines colloidal chemistry with two-steps of hierarchical self-assembly. First monodisperse submicron silica spheres slowly settle onto a flat substrate and self-organize as a (mostly) face-centered cubic (fcc) lattice that is periodic on an optical length scale. Second, this template serves as a three-dimensional scaffolding for the self-assembly of nanometer-scale CdSe colloidal quantum dots. Subsequently, the silica template is removed by selective etching and a three-dimensionally patterned material consisting solely of densely-packed semiconductor quantum dots is obtained. Therefore, the exact three-dimensional structure of the template is imprinted in the final material.