Role of nonequilibrium carrier distributions in multiple quantum well InGaAsP-based lasers

A microscopic model for the operation of multi-quantum well laser diodes is described. It includes bulk transport of carriers modeled by drift-diffusion equations, confined carriers in the quantum wells modeled by the Schroedinger equation, photon modes modeled by a Helmholtz equation and couplings described by rate equations. Application of this model shows that the carrier distribution in the active layer of the laser can not be described by quasi-equilibrium conditions. One consequence is the substantially non-uniform distribution of carriers among the quantum wells when the laser is biased above threshold. Another consequence is the observation of photoluminescence in wide area devices under short circuit conditions.