The present paper presents a theoretical analysis of electron emission, both thermionic and photoelectric, with moderate applied electric fields, based on a two-step potential barrier, a shape not employed hitherto as far as can be determined. An expression is obtained for thermionic emission current density with applied electric field containing two arbitrary constants, $V_1$ and $a$, the height and width of the first step of the barrier. Comparison of this expression with the experimental results of Phipps and Seifert yields reasonable values for the two constants. An expression is obtained also for photoelectric emission employing the same barrier shape in which insertion of the same values of $V_1$ and $a$ results in a periodic deviation of photo-current with applied electric field.

The present theoretical results for the photo-current vs. applied electric field are compared with those of Guth and Mullin.

• Received 29 December 1948

DOI:https://doi.org/10.1103/PhysRev.75.1599