Heteroepitaxial fabrication of binary colloidal crystals by a balance of interparticle interaction and lattice spacing

[Display omitted] The colloidal epitaxy utilizing a patterned substrate is used to fabricate colloidal crystals of the same structure and lattice spacing with the substrate, which is an effective technique for creating desired nanoscale architectures. However, this technique has been mainly limited to a single-component system. The colloidal epitaxy is versatile if multicomponent colloidal crystals can be produced, which is inspired by our previous study regarding binary colloidal crystals (b-CCs) fabricated at the edge of single-component crystals. We have examined various particle size combinations of binary colloidal mixture and substrates for heteroepitaxial growth of b-CCs. Colloidal crystallization was achieved through depletion attraction induced by added polymers. We demonstrated heteroepitaxial growth of b-CCs on the foreign colloidal crystals as the substrate. Under depletion attraction, deviation from equilibrium interparticle distance because of lattice mismatch between the substrate and epitaxial layers induces strain energy among the particles, yielding the b-CCs to attain minimum strain energy. Various types of b-CCs are created by adjusting the particle size ratio and polymer concentration. The heteroepitaxial growth technique enables the fabrication of complex multicomponent colloidal crystals that greatly facilitate versatile applications of the colloidal crystals.