Quantized electron transfer through random multiple tunnel junctions in phosphorus-doped silicon nanowires

Abstract

We have demonstrated numerically and experimentally that quantized electron transfer can be achieved in single-gated random multiple tunnel junctions. Extensive Monte Carlo simulations based on Coulomb blockade orthodox theory show that nonhomogeneous distributions of capacitances energetically favor one-by-one electron shuttling between the electrodes during each cycle of a gate voltage. This numerical prediction is supported by our experimental results on Si nanowire field-effect transistors with the channel moderately doped with phosphorus. Ionized dopants within the device channel locally modulate the potential, creating a naturally random one-dimensional multiple-tunnel-junction array. Under ac-gate operation, small current plateaus or inflections aligned at $\ifmmode\pm\else\textpm\fi{}nef$ appear in the ${I}_{d}\text{\ensuremath{-}}{V}_{d}$ characteristics, suggesting that quantized electron transfer is achievable in such naturally disordered systems.