Forward Characteristic of Germanium Point Contact Rectifiers

A quantitative discussion of the forward characteristic is given for point contact rectifiers. It shows that the theoretical value of d lnI/dV in the exponential region is nearly q/kT, and that the experimental slopes which are a fraction of this value cannot be the result of the spreading voltage. Recombination of injected carriers has little effect except at large currents beyond the exponential region. Relations are derived for the limit of very large currents, which show that γ approaches a value smaller than (1+b)−1, the hole concentration at the contact approaches a maximum value proportional to the equilibrium concentration of holes at the surface, and the spreading voltage becomes a linear function of the current.