Two step optimized process for scanning tunneling microscopy tip fabrication

Bastiman, F.; Cullis, A. G.; Hopkinson, M.; Briston, K J

doi:10.1116/1.3359608

Cited by 11 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the optimization of the process parameters for reproducibility and tip form/shape regulation is a concern. The latest attempts have come in the form of a basic electrochemical “drop-off” process to optimize tip manufacturing [ 21 ]. In this work, we have produced tips on three different electrochemical etching techniques which are AC, Meniscus and DC etching methods and also have produced some specific samples on each method as shown below in the experimental results.…”

Section: Resultsmentioning

confidence: 99%

Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

et al. 2021

View full text Add to dashboard Cite

Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM).

show abstract

Section: Resultsmentioning

confidence: 99%

Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The new trapping scheme requires nanometre-sized electrodes, readily available in the form of ultra-sharp STM tips. In [44], for instance, the authors present a two-step procedure for the routine production of ultra-sharp STM tips with a radius of curvature ranging from 3 to 10 nm. Even sharper electrodes with a tip radius of 1 nm are presented in [45].…”

Section: Electrodesmentioning

confidence: 99%

Nano trap for polar molecules

Blümel¹

2012

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

A new ac/dc monopole trap for neutral polar particles, introduced and explored by Blümel (2011 Phys. Rev. A 83 045402 and 2011 Eur. Phys. J. D 64 85-101), is significantly advanced in several directions. (1) Previously shown to work only for polar classical particles and polar macro-molecules, the trap is shown to work for polar diatomic molecules.(2) A homogeneous electric field, optionally switched on for improved stability in the angular direction, leads to stable trapping in higher order stability regions of the Mathieu equation. (3) Based on the Floquet formalism, analytical and numerical calculations are presented that show that the trap is quantum mechanically stable. (4) Definition and derivation of a quantum pseudo-potential allow a qualitative understanding of the quantum trapping mechanism. ( 5) It is shown that the proposed ac/dc trap may be realized experimentally using currently available scanning tunnelling microscopy technology.

show abstract

“…Systematic studies of tip etching parameters have been mostly limited to nonmagnetic W, whose electrochemistry differs notably from that of Cr. [13][14][15] A major practical advantage of bulk Cr tips is that they circumvent the need for complex ultra-high vacuum (UHV) cleaning and evaporation procedures, as well as in-situ tip exchange. However, the magnetic samples so far used to quantify spin polarization, e.g.…”

Section: Introductionmentioning

confidence: 99%

Etching of Cr tips for scanning tunneling microscopy of cleavable oxides

Huang

Liu

Zeljkovic

et al. 2017

Review of Scientific Instruments

View full text Add to dashboard Cite

We report a detailed three-step roadmap for the fabrication and characterization of bulk Cr tips for spin-polarized scanning tunneling microscopy. Our strategy uniquely circumvents the need for ultra-high vacuum preparation of clean surfaces or films. First, we demonstrate the role of ex situ electrochemical etch parameters on Cr tip apex geometry, using scanning electron micrographs of over 70 etched tips. Second, we describe the suitability of the in situ cleaved surface of the layered antiferromagnet LaSrMnO to evaluate the spin characteristics of the Cr tip, replacing the ultra-high vacuum-prepared test samples that have been used in prior studies. Third, we outline a statistical algorithm that can effectively delineate closely spaced or irregular cleaved step edges, to maximize the accuracy of step height and spin-polarization measurements.

show abstract

Two step optimized process for scanning tunneling microscopy tip fabrication

Cited by 11 publications

References 12 publications

Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

Nano trap for polar molecules

Etching of Cr tips for scanning tunneling microscopy of cleavable oxides

Contact Info

Product

Resources

About