Increased emission current from MIM cathodes through the use of a multilayer top electrode

Emission current density from metal-insulator-metal (MIM) cathodes has been increased by two orders of magnitude (5.8 mA/cm/sup 2/) through the use of a multilayer top electrode of Ir-Pt-Au (Ir layer at the top-electrode/insulator interface). The use of Ir, which has a high sublimation enthalpy, was effective for improving durability against diffusion of metal ions into the insulator. This property lets us apply a higher electric field (12-15 MV/cm) to the insulator than that of the MIM cathodes with a Au top-electrode we previously produced. A display demonstration of 30/spl times/30 MIM-cathode array with the proposed top-electrode showed excellent images on a phosphor screen. Moreover mechanism of hot-electron scattering in the top-electrode is also clarified.