Accession Number : AD0616202

Title :   THE USE OF A NEW POTENTIAL BARRIER MODEL IN THE FOWLER-NORDHEIM THEORY OF FIELD EMISSION,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK

Personal Author(s) : Cutler,P. H. ; Nagy,D.

Report Date : 31 AUG 1964

Pagination or Media Count : 28

Abstract : It is well known that for fields < or = 10 to the 7th power V/cm the observed field emitted current density is in agreement with the Fowler-Nordheim theory using the classical image-force barrier for the model of the surface potential. However, for fields > or = 5 x 10 to the 7th power V/cm, the measured current densities deviate from the linear log j versus 1/F curve, becoming progressively less than predicted values as the field increases. It was suggested that the departures from theory were due to space-charge distortions of the cathode field by high current densities. There are, however, other effects that occur at high fields which may also produce significant departures from the Fowler-Nordheim Law. One such possibility is the inaccuracy of the classical image-force barrier at small distances (several angstroms) from the surface. We have examined the effect of a modified surface potential barrier on the emitted current and energy distributions in the field emission region. The new potential represents quantum modifications to the classical imageforce and is based on quantum-mechanical calculations of the electronic potential in the surface region of a metal. The result for the current density is obtained in analytic form. Deviations from the linear FowlerNordheim plot begin about 5 x 10 to the 7th power V/cm and decrease progressively to a value about 4% lower at the highest fields. Energy distributions of the field emitted electrons have been calculated for the normal and total energy cases. These are given for the zero temperature limit and the T-F region. (Author)

Descriptors :   (*FIELD EMISSION, THEORY), (*POTENTIAL THEORY, FIELD EMISSION), QUANTUM THEORY, ELECTRONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE