Bismuth nanostructures of initial lateral size of about 150 nm were successfully electromigrated at room temperature under high vacuum conditions through the application of voltage ramps and accurate control of their conductance. The imaging of the nanogap formation was followed by scanning electron microscopy. An appropriate design of the initial Bi nanostructures has made the electromigration process of semimetallic Bi feasible. Beyond the intrinsic interest in the generation of Bi structures with size tailored at the nanoscale, remarkable features have been observed in the time-dependent conductance curves of the Bi nanoconstrictions. In particular, sub-quantum conductance plateaus can be detected before the rupture of the constriction. An alternative procedure to study the transport through Bi nanoconstrictions has been explored using a focused-Ga-ion etching process with simultaneous control of the conductance. This second approach confirms the transport behavior observed in electromigrated Bi nanoconstrictions.
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http://dx.doi.org/10.1039/c3cp44133d | DOI Listing |
ACS Appl Mater Interfaces
July 2024
Division of Micro and Nanosystems (MST), School of Electrical Engineering and Computer Science (EECS), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
Tunnel junctions have been suggested as high-throughput electronic single molecule sensors in liquids with several seminal experiments conducted using break junctions with reconfigurable gaps. For practical single molecule sensing applications, arrays of on-chip integrated fixed-gap tunnel junctions that can be built into compact systems are preferable. Fabricating nanogaps by electromigration is one of the most promising approaches to realize on-chip integrated tunnel junction sensors.
View Article and Find Full Text PDFACS Nano
September 2020
Experimental Physics of Nanostructured Materials, Q-MAT, CESAM, Université de Liège, Sart Tilman, B-4000 Liège, Belgium.
The past years have witnessed major advancements in all-electrical doping control on cuprates. In the vast majority of cases, the tuning of charge carrier density has been achieved electric field effect by means of either a ferroelectric polarization or using a dielectric or electrolyte gating. Unfortunately, these approaches are constrained to rather thin superconducting layers and require large electric fields in order to ensure sizable carrier modulations.
View Article and Find Full Text PDFACS Nano
October 2016
Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
Utilizing individual atoms or molecules as functional units in electronic circuits meets the increasing technical demands for the miniaturization of traditional semiconductor devices. To be of technological interest, these functional devices should be high-yield, consume low amounts of energy, and operate at room temperature. In this study, we developed nanodevices called quantized conductance atomic switches (QCAS) that satisfy these requirements.
View Article and Find Full Text PDFNat Commun
February 2016
INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
Superconducting nanowires currently attract great interest due to their application in single-photon detectors and quantum-computing circuits. In this context, it is of fundamental importance to understand the detrimental fluctuations of the superconducting order parameter as the wire width shrinks. In this paper, we use controlled electromigration to narrow down aluminium nanoconstrictions.
View Article and Find Full Text PDFLangmuir
July 2014
Mechanical Engineering Department, Stanford University, Stanford, California 94305, United States.
We present a detailed analysis of the transient pH dynamics for a weak, buffered electrolyte subject to voltage-driven transport through an ion-selective membrane. We show that pH fronts emanate from the concentration polarization zone next to the membrane and that these propagating fronts change the pH in the system several units from its equilibrium value. The analysis is based on a 1D model using the unsteady Poisson-Nernst-Planck equations with nonequilibrium chemistry and without assumptions of electroneutrality or asymptotically thin electric double layers.
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