Tungsten Schottky emitters with reservoirs of metal oxide or nitride

To obtain highly stable electron emission with a narrow energy width, we have investigated the electron emission characteristics of tungsten Schottky emitters made with various reservoir materials. The work functions of the adsorbed layers were calculated by using a simple electric dipole model, and we found that M1rOrW M1sSc, V, Y, Nb or La.and M2rNrW M2sTi, V, Y, Zr, Nb or La.compositions were expected to have a lower work function than that of the conventional ZrrOrW Schottky emitter. We formed M1rOrW and M2rNrW Schottky emitters and measured their electron emission properties. The ScrOrW, NbrOrW, and YrNrW Schottky emitters produced a continuous and confined electron beam at tip temperatures below 1800 K of the ZrrOrW Schottky emitter, and the energy widths of their Schottky-emitted electrons were equal to or narrower than the 0.4 eV of the ZrrOrW Schottky emitter. The ScrOrW Schottky emitter had the narrowest width at 0.25 eV. q1999 Elsevier Science B.V. All rights reserved.