Epitaxial Growth of Three-Dimensionally Mesostructured Single- Crystalline Cu2O via Templated Electrodeposition

Significant efforts have been made over the past few decades to realize functional three-dimensional photonic crystal devices including zero-threshold lasers, waveguides, light-emitting diodes (LEDs), and solar cells; however, progress has been limited because of difficulties in creating three-dimensional photonic crystals from single-crystal materials. Most have been formed from polycrystalline materials and thus have generally exhibited poor electronic properties. Realization of materials containing complex three-dimensional mesostructures, in single-crystal form, remains a significant challenge. Here, we demonstrate the epitaxial growth of three-dimensionally mesostructured Cu2O by bottom-up electrodeposition through a 3D silica colloidal template. Not only is the templated Cu2O single crystal, but when the electrodeposition continues past the colloidal template, the crystallinity of the overlying solid Cu2O appears to be improved because the template blocks threading dislocations, resulting in substantial reductions in the dislocation density of the overlying solid Cu2O.