Publication detail

Cleaning of tungsten tips for subsequent use as cold field emitters or STM probes

KOŠELOVÁ, Z. HORÁKOVÁ, L. BURDA, D. ALLAHAM, M. KNÁPEK, A. FOHLEROVÁ, Z.

Original Title

Cleaning of tungsten tips for subsequent use as cold field emitters or STM probes

Type

journal article in Web of Science

Language

English

Original Abstract

This study investigates the crucial process of cleaning cold field emission electron emitters and scanning tunnel microscopy (STM) probes, particularly focusing on tungsten tips. The cleanliness of these tips is essential for maintaining optimal cathode properties, preventing impurities that can significantly affect the emission process. Various cleaning methods, including macroetching, ammonia cleaning, and hydrofluoric acid (HF) cleaning were explored and compared by scanning electron microscopy. The macroetching method, involving a mixture of hydrochloric acid, nitric acid, and hydrogen fluoride, proved to be too reactive, causing significant material removal and altering the tip's structure. Ammonia cleaning did not significantly improve or harm the samples. However, oxide islands appeared in some areas, suggesting the potential formation of ammonium tungsten oxide. HF cleaning, specifically at 20% and 50% concentrations, demonstrated effectiveness in removing tungsten oxides without damaging the tip. Pre-cleaning with water and ethanol proved beneficial for subsequent HF refinement. Results suggest that HF is the most suitable method for oxide removal but a rinse with water is essential for removing residual sodium hydroxide. To maintain optimal properties, it is crucial to apply a less reactive layer quickly or transfer the tips to a water/ethanol bath to prevent oxidation.

Keywords

STM probes, field emission, cleaning procedure, tungsten tip, FEM

Authors

KOŠELOVÁ, Z.; HORÁKOVÁ, L.; BURDA, D.; ALLAHAM, M.; KNÁPEK, A.; FOHLEROVÁ, Z.

Released

31. 1. 2024

Publisher

FEI STU

Location

Bratislava

ISBN

1339-309X

Periodical

Journal of Electrical Engineering

Year of study

75

Number

1

State

Slovak Republic

Pages from

41

Pages to

46

Pages count

6

URL

http://iris.elf.stuba.sk/JEEEC/data/pdf/1_124-06.pdf

BibTex

@article{BUT187804,
  author="Zuzana {Košelová} and Lenka {Horáková} and Daniel {Burda} and Mohammad Mahmoud {Allaham} and Alexandr {Knápek} and Zdenka {Fohlerová}",
  title="Cleaning of tungsten tips for subsequent use as cold field emitters or STM probes",
  journal="Journal of Electrical Engineering",
  year="2024",
  volume="75",
  number="1",
  pages="41--46",
  doi="10.2478/jee-2024-0006",
  issn="1339-309X",
  url="http://iris.elf.stuba.sk/JEEEC/data/pdf/1_124-06.pdf"
}