Reformulation of basic semiconductor transport equations—II

The semiconductor transport equations are reformulated in terms of two new variables one of which measures the departure of the PN product from its equilibrium value and the other the space charge. The electric field is eliminated and the total current becomes the basic independent variable. Boundary conditions are found for these new variables which, being based on thermionic emission at the metal-semiconductor contact, are applicable under all circumstances where tunnelling is insignificant. Using these boundary conditions the terminal voltage is shown to divide into an internal ohmic term, a term dependent on the variation of the PN product and terms dependent on the conditions at the metal semiconductor contacts.