Wafer-scale controlled Au/Pt bimetallic flowerlike structure array

The combining of the bottom-up with top-down techniques is essential to construct novel micro-/ nano-materials according to the requirements of its end applications. This paper describes a pattern-directed method that combines the advantages of photolithography and electrochemical synthesis to construct a wafer-scale Au/Pt bimetallic flowerlike structure array. With this technique, Au/Pt bimetallic flowerlike structure arrays are homogeneously and highly-selectively synthesized from Au patterns with different spacing, dimensions and shapes on a 4-inch silicon wafer. The Au/Pt flowers are also well-constructed in the different designed array such as 'KAIST' and 'NOBEL'. The surface morphology of the Au/Pt flower was observed using scanning electron microscope (SEM). The chemical composition of the bimetallic flower was confirmed using energy dispersive spectrometer (EDS) and X-ray electron spectroscopy (XPS). The X-ray diffraction (XRD) patterns of the Au pitch and Si substrate on a wafer were studied to reveal the highly-selective growth from Au pitches. A time-dependent evolution clearly presents the different growth stages of Au/Pt flower. The analysis of Au/Pt flower growth process in an individual Au pitch shows an edge-selective particle development mechanism. The method can be applied to the construction of other interesting nano/microflower arrays of metals or metal oxides. The results would be helpful for the creation of the flower with regular physical attributes (shapes and sizes) and guiding the design of a perfect array for technological innovations.