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

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.

arXiv comment16 pages, 5 figures, submitted to Rev. Sci. Instrum

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• Observation of the hybridization gap and Fano resonance in the Kondo lattice URu2Si2
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• Andreev reflection and order parameter symmetry in heavy-fermion superconductors: the case of CeCoIn${}_5$
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Cited by in corpus (4)

• Hybridization gap in the heavy-fermion compound UPd${}_2$Al${}_3$ via quasiparticle scattering spectroscopy
• Design and construction of a point-contact spectroscopy rig with lateral scanning capability
• Origin of gap-like behaviors in URu${}_2$Si${}_2$: Combined study via quasiparticle scattering spectroscopy and resistivity measurements
• Systematic electrochemical etching of various metal tips for tunneling spectroscopy and scanning probe microscopy