Ultra-low breakdown voltage and origin of 1/f(2) noise in metallic nanorod arrays

The application of a dc voltage to an array of copper nanorods causes field evaporation of atoms from the tips, resulting in their progressive sharpening and a further increase in the local field. The process is self-limited by the build-up of space charge on the nanorod tips. From an analysis of the conductance noise recorded across the nanorod array, we show that the conduction mechanism bears a strong analogy with the stick-slip problem in sliding friction. The in situ sharpening results in an unprecedented lowering of the breakdown voltage of air by over 90%, as compared to plane parallel electrodes.