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arXiv · 1412.8201

Automated fabrication technique of gold tips for use in point-contact spectroscopy

S. Narasiwodeyar·M. Dwyer·M. Liu·W. K. Park·L. H. Greene
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Abstract

For a successful point-contact spectroscopy (PCS) measurement, metallic tips of proper shape and smoothness are essential to ensure the ballistic nature of a point-contact junction. Until recently, the fabrication of Au tips suitable for use in point-contact spectroscopy has remained more of an art involving a trial and error method rather than an automated scientific process. To address these issues, we have developed a technique with which one can prepare high quality Au tips reproducibly and systematically. It involves an electronic control of the driving voltages used for an electrochemical etching of a gold wire in an HCl-glycerol mixture or an HCl solution. We find that a stopping current, below which the circuit is set to shut off, is a single very important parameter to produce an Au tip of desired shape. We present detailed descriptions for a two-step etching process for Au tips and also test results from PCS measurements using them.

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S. Narasiwodeyar, M. Dwyer, M. Liu, W. K. Park, L. H. Greene. 2014-12-28. Automated fabrication technique of gold tips for use in point-contact spectroscopy. https://doi.org/10.1063/1.4913661

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