On the electrochemical etching of tips for scanning tunneling microscopy

Ibe, J. P.; Bey, P.; Brandow, Susan L.; Brizzolara, Robert A.; Burnham, Nancy A.; DiLella, D. P.; Lee, K. P.; Marrian, C. R. K.; Colton, Richard J.

doi:10.1116/1.576509

Cited by 375 publications

(166 citation statements)

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“…In this work, we simulate tips with cone angles from 15 to 25 • , a range which is practical for electrochemical etching methods. [32] The results are shown in Fig. 5.…”

Section: Tip Sharpness Influences the Field Enhancementmentioning

confidence: 86%

Local field enhancement of an infinite conical metal tip illuminated by a focused beam

Zhang

Cui

Martin

2009

J Raman Spectroscopy

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We present a systematic numerical investigation of conical metal tips which are commonly used in tip-enhanced Raman spectroscopy (TERS). Different from previous studies, we focus on how the tip length and the illumination condition influence the local field enhancement at the tip apex, and provide a useful reference for real experiments. In particular, we show that the type of illumination has a dramatic influence on the field enhancement: a localized illumination spot -as used in experiments -producing a very different response than a plane wave illumination -as usually used in previous models. Also, the effect of the different geometrical parameters, such as the sharpness of the tip apex and the cone angle, provides guidance to optimize the tip design. Finally, we investigate the influence of the substrate and compare numerical data with results deduced from a simplified model, finding good agreement. This brings new insights into the enhancement mechanism of TERS.

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“…In this work, we simulate tips with cone angles from 15 to 25 • , a range which is practical for electrochemical etching methods. [32] The results are shown in Fig. 5.…”

Section: Tip Sharpness Influences the Field Enhancementmentioning

confidence: 86%

Local field enhancement of an infinite conical metal tip illuminated by a focused beam

Zhang

Cui

Martin

2009

J Raman Spectroscopy

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“…By applying a dc bias between the partially submerged tungsten wire (anode) and the immersed stainless-steel electrode (cathode), a sharpened tungsten electrode with a smooth surface finish and emitter tip radius of tens of nanometers to tens of micrometers is formed [23]. Unfortunately, most liquid-metal coatings on smoothly etched needles tend to pull away from the needle apex in an effort to minimize area and surface energy.…”

Section: Description Of Apparatusmentioning

confidence: 99%

Regenerable Field Emission Cathode for Spacecraft Neutralization

Makela

Washeleski

King

2009

Journal of Propulsion and Power

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This research investigates the discharge characteristics of a field emission cathode for use in electric propulsion that has the ability to be regenerated when the emitter tip becomes damaged. Emitter tip regeneration is achieved by taking advantage of Taylor cone formation from an operating liquid-metal ion source. Tip formation is accomplished by solidifying, or quenching, the ion-emitting cone to preserve the sharp protrusion so that it can then be used for electron emission. Electron emission I-V curves were taken after tips were formed by quenching the liquid-metal ion source at ion discharge currents ranging from 1 to 25 A. Fowler-Nordheim modeling was then used to estimate the emitter tip radii of each quenched liquid-metal ion source. Results of the Fowler-Nordheim modeling were promising, showing the ability to regenerate tips and to control the features of the resulting tips by varying the ion current during the quench process. The set of experiments that are reported demonstrated the regeneration process of emitter tip radii ranging from approximately 30-45 nm from a tip quenched at 2 A down to tip radii of 15-22 nm when quenched at 25 A.

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“…Following the method and the set-up described by Ibe et al [7], an etching set-up was built in order to obtain tips with typical apex radii of 20-100 nm. Etching is done in 10%wt NaOH electrolyte.…”

Section: Electrochemical Etching Of Tungsten Tipsmentioning

confidence: 99%

Physical principles and miniaturization of spark assisted chemical engraving (SACE)

Wüthrich¹,

Hof²,

Lal³

et al. 2005

J. Micromech. Microeng.

107

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Spark assisted chemical engraving (SACE) is an unconventional micromachining technology based on electrochemical discharge phenomena for glass and various ceramics. The limits of SACE with respect to small dimensions in the particular case of glass are explored. It is found, using a specially developed set-up based on an AFM, that even using extremely sharp tool-electrodes does not allow us to produce a smaller pattern than typically 25 µm. It is concluded that the gas film thickness, in which the electrochemical discharges take place, is the main limiting factor. Further experimental investigations on its formation are investigated. By adding surfactants to the electrolyte, in order to increase the wettability of the tool-electrode and therefore to reduce the gas film thickness, it is observed experimentally that the critical voltage reduces significantly. This observation may lead to a novel method of characterizing the gas film thickness in SACE.

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On the electrochemical etching of tips for scanning tunneling microscopy

Cited by 375 publications

References 0 publications

Local field enhancement of an infinite conical metal tip illuminated by a focused beam

Local field enhancement of an infinite conical metal tip illuminated by a focused beam

Regenerable Field Emission Cathode for Spacecraft Neutralization

Physical principles and miniaturization of spark assisted chemical engraving (SACE)

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