Ultraviolet Photoemission Electron Microscopy

Ultraviolet photoemission electron microscopy is used to study the field emission of chromium oxide coated carbon nanosheets.

Carbon nanosheets, a two-dimensional carbon nanostructure, are promising electron cathode materials for applications in vacuum microelectronic devices. This letter demonstrates a simple approach to improve the spatial emission uniformity of carbon nanosheets by coating them with a chromium oxide thin film. Photoelectron emission microscopy observations and in situ field emission tests revealed that chromium oxide coated carbon nanosheets not only have spatial uniformity but also have coating thickness dependent field emission properties. For example, a coating thickness of ≈1.5 nm gave a substantially greater field emission than as-grown nanosheets or other thickness coatings.