Experimental Determination of the Current Density-Electric Field Relationship of Silicon Field Emitters

The field-emission projection microscope has been used to study the field-emission characteristics of several silicon cold cathodes. The current-voltage data from nine of these field-emitter tips were reduced to the more fundamental current density - electric field values after the tip geometry was determined in an electron microscope. Comparison of these results with the available theory by Stratton has shown only limited agreement. Two distinct forms have been found for the relationship between the field-emitted current I and the applied voltage V when plotted as log10 I vs 104/V. One form is ``nonlinear'' while the other is ``linear,'' and the difference between these appears related to the relative strength of a p layer present on the surface of the silicon field-emitter. A dependence of the field-emitted current on the temperature of the silicon tip has been observed.