Schottky‐barrier cold cathodes have been fabricated using Pd onn‐type ZnS. The Pd was deposited in the form of a film 30–50 Å thick on the freshly‐cleaved surface of the ZnS in an ultrahigh‐vacuum system, and cesiation was carried out without removal from the system. Cold emission currents up to 0.01 A/cm2were obtained with an efficiency as high as 1.5%. Barrier height measurements indicate that the electrons enter the junction at an energy level 0.5 eV above the vacuum level, but current characteristics reveal a loss process not yet identified.