Cathode-like luminescence from vacuum-dielectric interface induced by self-stabilizing secondary electron emission

A kind of interesting luminescence phenomenon from vacuum-dielectric interface under high electric field is presented in this Letter. It is visible, steady, and continuous, occurring before or accompanied with flashover across dielectric, which is quite different from general electroluminescence from insulator surface reported before. By investigating its optical and electrical characteristics, we consider it as cathode-like luminescence, which is initialized by the field electron emission from cathode triple junction and finally generated by the process of radiative recombination due to the self-stabilizing secondary electron emission and collision on insulator surface.