the very weak dependence of current on temperature.

Oppenheimer had mathematical details of his theory seriously incorrect. There was also a small numerical error in the final equation given by Fowler-Nordheim theory for CFE current density, corrected in a 1929 paper. 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 log(i/V²)