TIME-RESOLVED STUDY OF SELF-ASSEMBLED INAS QUANTUM DOTS

We have investigated the exciton kinetics in self-assembled InAs quant um dots and ultrathin quantum wells grown by molecular beam epitaxy on (001) oriented GaAs substrates. At low temperatures, the photolumines cence decay time of the quantum wells increases almost linearly while the decay time of the quantum dot system is independent of temperature . However, above 50 K there is a linear increase in the decay time of the dots which may be due to electrons escaping into the wetting layer or occupation of nonradiative exciton states. Under the conditions of high injection, relaxation from the excited states has a time constan t of about 500 ps. (C) 1996 American Institute of Physics.