TIME-RESOLVED LUMINESCENCE STUDY OF BIEXCITONS IN CUCL QUANTUM DOTS

Population dynamics of excitons and biexcitons in nanometer-sized CuCl microcrystallites (nanocrystals) was studied with a time-resolved lum inescence measurement. A recurring process between excitons and biexci tons was clearly observed as a function of the second decay component of the biexciton luminescence and with an increase of the exciton lumi nescence. They become prominent with an increase in the excitation int ensity. The biexciton luminescence is broadened asymmetrically to high er energy with an increase in the biexciton density. These temporal as well as spectral characteristics of biexciton luminescence are inhere nt to CuCl nanocrystals but are not observed in a CuCl bulk crystal, w hich shows that biexcitons are much more efficiently formed from excit ons in a CuCl nanocrystal than in a CuCl bulk crystal.