Arrays of sputtered tungsten thermionic emitters with different shapes have been fabricated. A single filament had an emission current of 10 nAmps and a one hour lifetime. The resistance of a filament decreased an order of magnitude with 25 minutes of annealing. After emission the filament appears to have recrystallized in the emitting area. The surface roughness of the recrystallized area strongly depends on the duration of annealing and emitting time. The variation of filament resistance during operation has been investigated. A thermionic emitter has been used as a source for a sub-cm electron optical column. An array of emitters could be used as a high resolution cathode ray tube if the supports are made from a low thermal conductivity material like glassy carbon with thermal conductivity of 10-3 watt/cm-K1.