Tungsten Schottky emitters with reservoirs of metal oxide or nitride

To obtain highly stable electron emission with a narrow energy width, we ha ve investigated the electron emission characteristics of tungsten Schottky emitters made with various reservoir materials. The work functions of the a dsorbed layers were calculated by using a simple electric dipole model, and we found that M1/O/W (M1 = Sc, V, Y, Nb or La) and M3/N/W (M2 = Ti, V, Y, Zr, Nb or La) compositions were expected to have a lower work function than that of the conventional Zr/O/W Schottky emitter, We formed M1/O/W and M2/ N/W Schottky emitters and measured their electron emission properties. The Sc/O/W, Nb/O/W, and Y/N/W Schottky emitters produced a continuous and confi ned electron beam at tip temperatures below 1800 K of the Zr/O/W Schottky e mitter, and the energy widths of their Schottky-emitted electrons were equa l to or narrower than the 0.4 eV of the Zr/O/W Schottky emitter. The Sc/O/W Schottky emitter had the narrowest width at 0.25 eV. (C) 1999 Elsevier Sci ence B.V. All rights reserved.