On an approximation in space-charge-current theory

Examination of the approximation, commonly made in the theory of space-charge-limited current, that the concentration of thermally generated free electrons is constant. It is shown that the concentration of ionized donors is not always the same at all points and for all levels of injection, but that as the applied voltage is increased through the transition range the donors will be progressively reoccupied at the expense of the space charge and thus will tend to restrain the upward movement of the local quasi-Fermi level.