Biexcitons in the semiconductor Cu2O:: An explanation of the rapid decay of excitons -: art. no. 241201

Excitons in the semiconductor Cu2O exhibit a puzzling density-dependent lifetime that severely limits the attainable gas density. Our previous experimental work on this nearly ideal gas points to an anomalously strong Auger recombination process. The observed exciton decay rate is over five orders of magnitude larger than present theoretical estimates indicate for this crystal. Based on time- and space-resolved photoluminescence studies, we propose that the exciton densities are limited by their binding into short-lived excitonic molecules.