Cooperative Effects of Confinement and Surface Functionalization Enable the Formation of Au/Cu2O Metal-Semiconductor Heterostructures

A promising approach to obtaining multifunctional materials with tunable properties is the incorporation of second phase constituents (e.g., particles, fibers) within inorganic crystals. To date, however, the specific chemical and physical controls over incorporation are only known for a few select systems. In this study, a simple wedge is used as a confining structure to systematically control the chemical and physical aspects of the crystallization microenvironment to promote the interaction between copper(I) oxide (Cu2O) crystals and alkanethiol-functionalized gold nanoparticles (Au np), producing a metal–semiconductor composite. Physically, the confining wedge geometry provides (vapor) diffusion-limited growth conditions. Chemically functionalizing both the Au np surfaces and the glass slides that form the wedge promotes the interaction of Au np with the growing Cu2O crystals. The physical confinement of the wedge structure, as well as optimization of its surface chemistry, is required to achieve this interaction. These findings demonstrate that Au/Cu2O can be used as a model system to inform the synthesis of other metal–semiconductor heterostructures.