Résumé
The dynamics of the free-exciton capture by boron acceptors and phosphorus donors in diamond is observed in the picosecond range by time-resolved photoluminescence experiments at low temperature. The formation of boron-bound excitons is observed with a delay of 410 ps after the formation of free excitons. For phosphorus, this delay is 120 ps. This is the result of the free-exciton capture by B° and P° impurities. The lifetimes of boron- and phosphorus-bound excitons are measured and found to be equal to 270 and 70 ps, respectively. These values are about four orders of magnitude shorter than for the same impurities in silicon. Ei being the ionization energy of dopants, these results scale well with the Ei4 dependence of the Auger recombination rate expected for bound excitons in indirect band-gap semiconductors.