Abstract
The simplest electrical model of the injection laser assumes that the active layer, the layer in which spontaneous and stimulated radiative recombination take place, is a homogeneous layer. The only parameters of such an electrical model are the thick¬ ness of the active layer, and the electron and hole concentrations and quasi-Fermi levels. If such a model is combined with an optical model with no k-selection rule,1one obtains reasonable agreement with experimental threshold current densities, particularly if energy band tails are taken into account.2The theory, however, predicts a superlinear relation between gain constant and current density near room temperature, while the observed relation is linear.3 Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.