Electron emission mechanism of diamond characterized using combined x-ray photoelectron spectroscopy/ultraviolet photoelectron spectroscopy/field emission spectroscopy system

Clarification on electron emission mechanism of diamond is one essential approach to realize the clear vision of vacuum nanoelectronics. Electric field of less than $5V∕μm$ is enough to extract electrons from diamond, whereas field of one to two orders of magnitude higher is needed to extract electrons from conventional metal emitter tips. Diamond has various advantages as an electron emitter in addition to the low-threshold voltage, such as negative electron affinity and high thermal conductivity. The difficulty in clarification of electron emission mechanism is the factor preventing diamond from being used in a practical way. In this study, combined spectroscopy of x-ray photoelectron spectroscopy/ultraviolet photoelectron spectroscopy/field emission spectroscopy was performed to characterize the electron emission mechanism of diamond. The results indicated the first successful observation of applied voltage dependence on the origin of field-emitted electrons.