CARRIER RECOMBINATION RATES IN STRAINED-LAYER INGAAS-GAAS QUANTUM-WELLS

The carrier recombination rates in semiconductor quantum wells are found to be structure dependent, and under high levels of excitation, generally do not follow the recombination rule of the bulk material. Through a differential carrier-lifetime measurement in the strained-layer InGaAs-GaAs quantum wells, we show that in quantum wells with lower potential barrier or thinner well width, the recombination rates are smaller due to a larger portion of the injected carriers populating the confinement layers where the carriers recombine more slowly owing to diluted carrier volume density. The present study indicates that the carrier recombination rate is not an intrinsic property of the material composition, and that a simple recombination rule based on the power series of carrier density is, in general, not applicable in quantum wells.