Effects of palladium coating on field-emission properties of carbon nanofibers in a hydrogen plasma

• Carbon nanofibers were uniformly coated with palladium.
• Energy-filtered transmission electron microscope confirms uniformity of coating.
• Tips were exposed to atomic hydrogen environment.
• Field emission characteristics were measured and compared to uncoated samples.
• Coated samples show better field emission properties and longer lifetime.

Results from electron field-emission studies using arrays of patterned carbon nanofiber bundles are reported. We find that the desired field-emission characteristics were not compromised when a protective coating consisting of a layer of palladium of 5 and 30 nm thickness was applied. Following exposure to a hydrogen plasma for several hours we find that the coatings impede plasma damage significantly, whereas the field-emission properties of uncoated nanofibers degraded much more rapidly. The results demonstrate that carbon nanofibers with protective conformal metal coatings can be integrated into harsh plasma environments enabling a range of applications such as field-ionization ion sources and advanced (micro)-plasma discharges.