Characteristics of the single-electron conduction properties of randomly distributed metal nanodot arrays

Abstract

Multi-dot single-electron devices (SEDs) have been fabricated using very thin Fe films by vacuum deposition on thermally oxidized or sputter-deposited SiO2 substrates. Although the SEDs fabricated on the two substrates showed very different conductance, Coulomb blockade (CB) oscillation clearly appeared in certain Fe thickness ranges for both cases. The CB oscillation changed from complex to simple with increasing Fe thickness, indicating that the decrease of the number of dots contributed to the CB oscillation. While the simple CB monotonically disappeared by the drain voltage (V D), the complex CB was robust against V D because V D distributes over the array composed of plural dots. The CB property change from complex to simple appeared in different thickness ranges for the two substrates, but in similar conductance ranges. This demonstrates that the conductance influenced by the inter-dot distance is an important factor for the CB characteristics of randomly distributed multi-dot SEDs.