OBSERVATIONS OF A FIELD-FORMING PROCESS FOR ZNO-W COLD CATHODES

Authors
Citation
Ms. Mousa, OBSERVATIONS OF A FIELD-FORMING PROCESS FOR ZNO-W COLD CATHODES, Vacuum, 45(2-3), 1994, pp. 245-248
Citations number
15
Categorie Soggetti
Physics, Applied
Journal title
VacuumACNP
ISSN journal
0042207X
Volume
45
Issue
2-3
Year of publication
1994
Pages
245 - 248
Database
ISI
SICI code
0042-207X(1994)45:2-3<245:OOAFPF>2.0.ZU;2-K
Abstract
Studies of techniques for preparing zinc oxide-coated tungsten microem itters, their emission characteristics and the stability of their emis sion currents have been recently published, in this paper, the influen ce of thermal treatment of the cathode while the emission current leve l is similar to 10 mu A has been investigated. At temperatures of simi lar to 700 degrees C the current showed a considerable increase in val ue for the same applied anode voltage. Though the anode voltage was re duced by approximately 25-30% the cathode produced the same emission c urrent. It is believed that this enhancement is caused by the release of gases, mainly oxygen, from the composite tip, and there is also the possibility of bombardment from the anode screen by phosphor atoms (a nd conceivably other atoms too). The behaviour of the cathode as well as its current-voltage (I-V) characteristics resembled the well known thermal field-forming process, although the effect on the current emit ted was smaller. The enhancement in the emission current has been show n experimentally to be permanent and to produce reversible I-V charact eristics The change in the I-V characteristics indicate that relativel y large changes in the work function of the ZnO-W composite cathode ha ve taken place.