Electron emission properties of surface-conduction electron emitters with a PdO-C-PdO multilayer conductive film deposited by magnetron sputtering

Conductive films are an essential component in surface-conduction electron emitters (SCEs), and they have a major influence on the electron emission properties of SCEs. In this work, a novel PdO-C-PdO multilayer film deposited by magnetron sputtering is proposed as the conductive film in SCEs. Three SCE cathodes with this type of multilayer film were fabricated, together with three other SCE cathodes with a PdO single-layer film used as a reference. For these cathodes, the dependences of the conduction current and the emission current on the device voltage and the anode voltage were measured, and the luminescence patterns were observed after the electroforming and activation processes of the conductive films had occurred. The surface morphologies of the conductive films were analyzed by scanning electron microscopy. The results indicate that the SCEs with the PdO-C-PdO multilayer conductive film have better electron emission properties compared with the SCEs with the PdO single-layer conductive film. For an anode voltage of 2 kV and a device voltage of 14 V, the emission current and the electron emission ratio of the SCEs with the PdO-C-PdO multilayer film can reach 179.5 μA and 2.2‰, respectively.