Mechanisms of Auger recombination in quantum wells

The main mechanisms for the Auger recombination of nonequilibrium carriers in semiconductor quantum-well heterostructures are investigated. It is shown for the first time that there are three fundamentally different Anger recombination mechanisms in quantum wells: 1) a threshold-free mechanism, 2) a quasithreshold mechanism, and 3) a threshold mechanism. The rate of the threshold-free process has a weak temperature dependence. The rate of the quasithreshold Auger process exhibits an exponential temperature dependence. However, the threshold energy depends significantly on the quantum-well width and is close to zero for narrow quantum wells. It is shown that the threshold-free and quasithreshold processes are dominant in fairly narrow quantum wells, while the quasithreshold and threshold Auger processes are dominant in wide quantum wells. The limiting transition to a three-dimensional Auger process is accomplished for a quantum-well width tending to infinity. The value of the critical quantum-well width, at which the quasithreshold and threshold Anger processes combine to form a single three-dimensional Auger recombination process, is found. (C) 1998 American Institute of Physics.