Surface composition of Si-TaSi2 eutectic cathodes and its effect on vacuum field emission

Abstract
Our research shows that the presence of an oxide layer on the surface of a field emission cathode is deleterious to its performance and that, for successful operation, removal of this layer is necessary before overcoating with another material. We further show that once the surface oxide is removed, cathodes can be protected with a Au overcoat and run in harsh environments. We have demonstrated stable emission for a Au‐coated Si‐TaSi2 cathode for over 100 h in an O2 atmosphere at 5×10−6 Torr.