Open Access Research Article Issue
Lithography-Free Fabrication of High Quality Substrate-Supported and Freestanding Graphene Devices
Nano Research 2010, 3 (2): 98-102
Published: 27 March 2010

We present a lithography-free technique for fabrication of clean, high quality graphene devices. This technique is based on evaporation through hard Si shadow masks, and eliminates contaminants introduced by lithographical processes. We demonstrate that devices fabricated by this technique have significantly higher mobility values than those obtained by standard electron beam lithography. To obtain ultra-high mobility devices, we extend this technique to fabricate suspended graphene samples with mobilities as high as 120 000 cm2/(V·s).

Open Access Research Article Issue
Phase Diffusion in Single-Walled Carbon Nanotube Josephson Transistors
Nano Research 2008, 1 (2): 145-151
Published: 01 February 2008

We investigate electronic transport in Josephson junctions formed by individual single-walled carbon nanotubes coupled to superconducting electrodes. We observe enhanced zero-bias conductance (up to 10e2/h) and pronounced sub-harmonic gap structures in differential conductance, which arise from the multiple Andreev reflections at superconductor/nanotube interfaces. The voltage-current characteristics of these junctions display abrupt switching from the supercurrent branch to the resistive branch, with a gate-tunable switching current ranging from 65 pA to 2.5 nA. The finite resistance observed on the supercurrent branch and the magnitude of the switching current are in good agreement with the classical phase diffusion model for resistively and capacitively shunted junctions.

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