Cesium intercalation of graphene: A 2D protective layer on alkali antimonide photocathode
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Euclid Techlabs, Bolingbrook, IL (United States)
- Argonne National Lab. (ANL), Lemont, IL (United States)
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
Alkali antimonide photocathodes have wide applications in free-electron lasers and electron cooling. The short lifetime of alkali antimonide photocathodes necessitates frequent replacement of the photocathodes during a beam operation. Furthermore, exposure to mediocre vacuum causes loss of photocathode quantum efficiency due to the chemical reaction with residual gas molecules. Theoretical analyses have shown that covering an alkali antimonide photocathode with a monolayer graphene or hexagonal boron nitride protects it in a coarse vacuum environment due to the inhibition of chemical reactions with residual gas molecules. Alkali antimonide photocathodes require an ultra-high vacuum environment, and depositing a monolayer 2D material on it poses a serious challenge. In the present work, we have incorporated a novel method known as intercalation, in which alkali atoms pass through the defects of a graphene thin film to create a photocathode material underneath. Initially, Sb was deposited on a Si substrate, and a monolayer graphene was transferred on top of the Sb film. Heat cleaning around 550–600 °C effectively removed the Sb oxides, leaving metallic Sb underneath the graphene layer. Depositing Cs on top of a monolayer graphene enabled the intercalation process. Atomic force microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, low energy electron microscopy, and x-ray diffraction measurements were performed to evaluate photocathode formation underneath the monolayer graphene. Our analysis shows that Cs penetrated the graphene and reacted with Sb and formed Cs3Sb.
- Research Organization:
- Euclid Techlabs, LLC, Bolingbrook, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0021511; SC0012704; AC02-06CH11357; AC02−76SF00515
- OSTI ID:
- 1898420
- Alternate ID(s):
- OSTI ID: 1898175; OSTI ID: 1907828
- Report Number(s):
- BNL-223841-2023-JAAM; TRN: US2310898
- Journal Information:
- APL Materials, Vol. 10, Issue 11; ISSN 2166-532X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
photocathodes
intercalation
2D materials
graphene
electron microscopy
thin films
intercalation compounds
atomic force microscopy
x-ray photoelectron spectroscopy
x-ray diffraction
ultra-high vacuum
36 MATERIALS SCIENCE
GaAs
photocatodes
electron affinity
low energy electron microscopy