| 摘要 |
A cathode (14) is formed of an alloy, which contains 0.01 to 5 mol% of scandium and 0.01 to 0.3 mol% of alkali metal. Base of the alloy has work function greater than or equal to 4 eV and is silver, aluminum, or indium or the alloy thereof. Thickness of the cathode (14) is preferably 1 to 30 nm. Also, as a cathode protection layer (15), an aluminum alloy is formed on the cathode in a thickness greater than or equal to 50 nm, the aluminum alloy containing 0.1 to 5 mol% of silicon, copper, scandium and/or manganese. |
