Abstract
Modeling of the I(V, T) dependence in thin p-n semiconductor structures shows that various behaviors in its shape factor can be correlated with and explained through the voltage dependence of the carrier concentration product np and its components, at the zero field injection-point, for various conditions controlled by thickness and doping. A ''second exponential'' high injection range exp (qV/nkT), with a shape factor n as high as four appears to be a consequence of the departure from quasineutrality due to significant minority carrier space charge, favored by low doping and thickness. In thin structures, the presence of a second exponential range is associated with the presence of a quadratic range (I similar to V-2) at very high current densities.