Ultra-thin gold nanowires with uniform diameters of 2 nm and lengths of over 100 μm are synthesized via the reduction of gold(III) chloride in an oleylamine matrix. The gold nanowires, dispersed on an oxidized substrate, are top-contacted with metallic electrodes to manufacture back gated transistors. We investigate the transport properties in the fabricated devices as a function of the gate voltage, the bias voltage, and the temperature. The nonlinear current-bias voltage characteristics from 7 K up to 300 K are well described by the Coulomb blockade model in a nearly one-dimensional quantum dot array (which results from the gold nanowires’ thermal fragmentation into a granular material). Our results support a picture in which the electronic transport is governed by sequential tunneling at an applied bias above the global Coulomb blockade threshold, whereas in the Coulomb blockade regime, inelastic cotunneling is dominant up to 70 K, at which point it crosses over to activated behavior. The current dependence on the gate voltage that shows irregular oscillations is well explained by the superimposition of Coulomb oscillation patterns generated by each different dot in the one-dimensional array. We find that the competitive effects of excitation energy and stochastic Coulomb blockade balance the number of current peaks observed.
Single electron transistors exhibiting transport properties based on a single Coulomb island have been fabricated using ultra-thin gold nanowires (AuNWs), which are synthesized via a chemical reduction process. The AuNWs are bottom-contacted with source and drain electrodes to avoid damaging the AuNWs under fabrication processes. We investigate the transport properties in the fabricated devices as a function of the bias and gate voltages at room and low temperatures. At 0.23 K, the periodical Coulomb oscillations and diamonds are clearly observed indicating that an individual AuNW acts as a single Coulomb island. These transport properties can be explained by the orthodox Coulomb blockade theory.
Uniform, 2 nm diameter gold nanowires were synthesized through the reduction of gold(III) chloride in an oleylamine matrix. They were top-contacted on a Si/Si02 substrate with metallic electrodes to manufacture back-gated transistors. Due to thermal breakage, the gold nanowires were fragmented into a granular material and the non-linear current-bias voltage characteristics measured on the devices from 7 K up to 300 K were described by the Coulomb blockade theory in a nearly one-dimensional quantum dot array. The electronic transport was governed by sequential tunneling at an applied bias above the global Coulomb blockade threshold, whereas in the Coulomb blockade regime, inelastic cotunneling was dominant up to 70 K, at which point it crossed over to activated behavior. The current dependence on the gate voltage that showed irregular oscillations was explained by the superimposition of Coulomb oscillation patterns generated by each different dot in the one-dimensional array. The competitive effects of excitation energy and stochastic Coulomb blockade balanced the number of current peaks observed.
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