abstract |
An electron emitter (121, 221, 321, 421) includes an electron emitter structure (118) having a passivation layer (120, 220, 320, 420) formed thereon. The passivation layer (120, 220, 320, 420) is made from an oxide selected from a group consisting of the oxides of Ba, Ca, Sr, In, Sc, Ti, Ir, Co, Sr, Y, Zr, Ru, Pd, Sn, Lu, Hf, Re, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Th, and combinations thereof. In the preferred embodiment, the electron emitter structure (118) is made from molybdenum, and the passivation layer (120, 220, 320, 420) is made from an emission-enhancing oxide having a work function that is less than the work function of the molybdenum. |