Hole-electron product of pn junctions

Assertions that the hole-electron product may be larger than ni2 exp (qV/kT) under high injection conditions are found in the old and recent literature. This paper shows that the np product must always be ⩽ ni2 exp(qV/kT). Plots of numerical results for electrostatic potential, quasi-fermi levels and carrier concentration for an asymmetrical np junction under low and high injection conditions are given.