Surface characterization of zirconia-coated tungsten Schottky emitters by using RHEED, AES, and TOF-SIMS

The current study investigates the diffusion of a Zr–O complex on a W substrate, which is one of the surface components of the Schottky electron source. To enable the thermal diffusion of Zr atoms with the assistance of oxygen, the source was heated to approximately 1800 K; this enabled the Zr–O complex to reach the electron emission area at the source apex, which was several hundred micrometers away from the Zr reservoir. At such a high temperature, the evaporation rate of surface components also increased, making it more difficult for the atoms to diffuse farther. To better understand the mechanisms underlying diffusion and evaporation, the amount of Zr on the surface was estimated using Auger electron spectroscopy. The surface coverage of the Zr–O complex was found to be almost constant up to 600 μm without any significant loss. Furthermore, the diffusion of the Zr–O complex was found to be more dominant than evaporation, resulting in coverage saturation. However, when coverage of the Zr–O complex decreased, the observed trends changed drastically, which suggests that the balance of diffusion and evaporation cannot be described by a simple material balance equation. Additionally, the range with a fully covered area of the Zr–O complex became narrower at temperatures higher than 1900 K. These features, however, varied depending on the vacuum level surrounding the sample. Based on these findings, the diffusion and evaporation model of Zr and O on the surface of the Schottky electron source is proposed.

show abstract

Electron emission from HfC(100) single-crystal tip

Kusunoki,

Arai

2024

Journal of Vacuum Science &Amp; Technology B

View full text Add to dashboard Cite

We investigated electron emission characteristics of a hafnium carbide [HfC(100)] single-crystal tip at various temperatures toward finding a candidate of the next generation of emitters for electron microscopes. The emission mode changed from cold-field emission (CFE) to low-temperature and high-temperature thermal-field emission and, finally, to extended Schottky emission. The energy width at full width of half maximum of the emitted electrons was 0.2 eV in the CFE mode at an angular current of 20 μA/sr, and it showed good emission stability with current noise less than 3.5% in an electron gun of a scanning electron microscope (SEM). Spatial resolution of the SEM at an acceleration voltage of 0.5 kV improved 14% by using the HfC(100)-CFE tip instead of a conventional W(310)-CFE tip. High monochromaticity and stable electron emission of the HfC(100)-CFE tip are suitable for the next generation of emitters for ultrahigh-resolution field emission SEMs.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Surface characterization of zirconia-coated tungsten Schottky emitters by using RHEED, AES, and TOF-SIMS

Cited by 5 publications

References 30 publications

Oxidation state of zirconium and tungsten on a Schottky electron source at high temperature

Oxidation state of zirconium and tungsten on a Schottky electron source at high temperature

Diffusion of zirconium on the surface of Schottky electron sources

Electron emission from HfC(100) single-crystal tip

Contact Info

Product

Resources

About