Low-voltage electron transport in self-assembled nanocrystal arrays

Electrons traverse two-dimensional nanocrystal arrays by sequential tunneling between neighboring nanocrystals. Analysis of array conductance at zero bias-voltage gives information about underlying nanocrystal uniformity, as well as the relevant single-electron charging energy. We discuss low-temperature measurements of two-dimensional self-assembled superlattices composed of 10 nanometer diameter cobalt nanocrystals, with ∼2 nm inter-nanocrystal spacing.