Bottom-up synthesis of ultrathin straight platinum nanowires: Electric field impact

We present a study of the electric field effect on electrochemically grown ultrathin, straight platinum nanowires with minimum diameter of 15 nm and length in the micrometer range, synthesized on a silicon oxide substrate between metal electrodes in HPtCl solution. The influence of the concentration of the platinumcontaining acid and the frequency of the applied voltage on the diameter of the nanowires is discussed with a corresponding theoretical analysis. We demonstrate for the first time that the electric field profile, provided by the specific geometry of the metal electrodes, dramatically influences the growth and morphology of the nanowires. Finally, we provide guidelines for the controlled fabrication and contacting of straight, ultrathin metal wires, eliminating branching and dendritic growth, which is one of the main shortcomings of the current bottom-up nanotechnology. The proposed concept of self-assembly of thin nanowires, influenced by the electric field, potentially represents a new route for guided nanocontacting via smart design of the electrode geometry. The possible applications reach from nanoelectronics to gas sensors and biosensors. [Figure not available: see fulltext.] © 2013 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.