RF Sputtering Coating of Electron Transparent Materials for Photocathode Encapsulation
- Euclid Techlabs, LLC
Statement of the problem: Alkali antimonide photocathodes are commonly used in high brightness photoinjectors because of their ultra-high quantum efficiency and relatively low requirements for growth. The biggest challenge of using the alkali antimonide photocathode is that it has an extremely stringent requirement on vacuum and can be destroyed by even low doses of residual gas. Consequently, the transportation of alkali antimonide photocathodes is eminently difficult. Furthermore, the cathode lifetime is limited by the residual gas in the photoinjector. An efficient encapsulation is needed to avoid contamination during transportation of photocathodes and preserve their lifetime. How the problem is being addressed: We are encapsulating the photocathodes with thin-film coatings through RF sputtering, which can be easily configured to work with various facilities and produce photocathodes that are robust against poor vacuum. We are also developing a laser oscillator deposition enhancement system (LODES) to improve the thin-film quality without damaging the substrates. We will keep optimizing the sputtering recipe aiming for 2D material (hBN) forms, investigating the LODES effectiveness, and characterizing the encapsulation. What was done in Phase I: We have accomplished more than the Phase I proposal deliverables: We completed the density functional theory (DFT) simulations of the encapsulated photocathodes and estimated the effectiveness of the thin-film protection against oxygen adatoms; We designed, fabricated and tested a UHV-compatible high-power sputtering system, “Turmeric”, which is compatible with the BNL puck photocathode base; We successfully obtained densely packed BN nanostructure thin-films on both Si and Cu (111) substrates using RF sputtering and characterized them using SEM and XPS; We designed, fully simulated and preliminarily built a LODES; We measured enhanced photocurrent from an encapsulated Cu (111) compared to an uncoated one.
- Research Organization:
- Euclid Techlabs LLC, Cleveland, OH (United States)
- Sponsoring Organization:
- USDOE
- Contributing Organization:
- BNL
- DOE Contract Number:
- SC0020573
- OSTI ID:
- 1771147
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- DOE - Euclid Techlabs - PH1 - 20573; 20573
- Country of Publication:
- United States
- Language:
- English
Similar Records
Cesium intercalation of graphene: A 2D protective layer on alkali antimonide photocathode
Active bialkali photocathodes on free-standing graphene substrates