Formation of symmetric and asymmetric metal-semiconductor hybrid nanoparticles

Multi-component nano-systems are created by combining two or more different materials yielding new chemical and physical properties. Here we report the selective anisotropic growth creating hybrid nanparticles of two different material systems, a metal onto a semiconductor. We developed a simple method for the selective growth of gold tips onto the apexes of colloidal semiconductor nanorods and tetrapods. This combination provides new functionalities to the nanostructures, the most important of which is the formation of natural anchor points that can serve as a recognition element for directed self assembly and for wiring them onto electrical circuitry. At higher gold concentrations we observe a transition from two to one-sided gold growth. This behavior is attributed to a ripening process as was also studied using a theoretical model.