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.