F is a better working limit : this corresponds to a " ? " " T "-value of around 1.09, and ( for the example case ) an upper temperature limit on the CFE regime of around 1770 K . This limit is a function of barrier field.
12.
This function " s " was first tabulated correctly ( as a function of the Nordheim parameter " y " ) by Burgess, Kroemer and Houston in 1953; and a modern treatment that gives " s " as function of the scaled barrier field " f " for a Schottky-Nordheim barrier is given in.
13.
Strictly, if the barrier field in Fowler-Nordheim 1928 theory is exactly proportional to the applied voltage, and if the emission area is independent of voltage, then the Fowler-Nordheim 1928 theory predicts that plots of the form ( log ( " i " / " V " 2 ) vs . 1 / " V " ) should be exact straight lines.
14.
In the FEM image, dark areas correspond to regions where the local work function " ? " is relatively high and / or the local barrier field " F " is relatively low, so " J " is relatively low; the light areas correspond to regions where " ? " is relatively low and / or " F " is relatively high, so " J " is relatively high.
