Auger recombination in semiconductor quantum wells

Abstract

The principal mechanisms of Auger recombination of nonequilibrium carriers in semiconductor heterostructures with quantum wells (QW's) are investigated. It is shown that there exist three fundamentally different Auger recombination mechanisms of (i) thresholdless, (ii) quasithreshold, and (iii) threshold types. The rate of the thresholdless Auger process depends on temperature only slightly. The threshold energy of the quasithreshold process essentially varies with QW width and is close to zero for narrow QW's. It is shown that the thresholdless and the quasithreshold Auger processes dominate in narrow QW's, while the threshold and the quasithreshold processes prevail in wide QW's. The limiting case of a three-dimensional (3D) Auger process is reached for infinitely wide QW's. The critical QW width is found at which the quasithreshold and threshold Auger processes merge into a single 3D Auger process. Also studied is phonon-assisted Auger recombination in QW's. It is shown that for narrow QW's the act of phonon emission becomes resonant, which in turn increases substantially the coefficient of phonon-assisted Auger recombination.