Photoluminescence decay time measurements from self-organized InAs/GaAs quantum dots

In this article we report the results of time integrated and time resolved photoluminescence spectroscopy and photoluminescence time decay measurement s as a function of excitation density at 6 K on high quality self-organized InAs/GaAs quantum dots. To understand the form of the experimentally obser ved photoluminescence transients a Monte Carlo model has been developed tha t allows for the effects of random capture of photo-excited carriers. By co mparison with the results of our model we are able to ascribe the excitatio n density dependence of the overall form of the decay of the emission from the quantum dot ground states and the biexponential nature of the decay of the first excited state emission as being due to the combined effects of ra diative recombination, density dependent carrier scattering, and the restri ction of carrier scattering due to state blocking caused by the effects of Pauli exclusion. To successfully model the form of the biexponential decay of the highest energy excited states we have to invoke the nonsequential sc attering of carriers between the quantum dot states. (C) 1999 American Inst itute of Physics. [S0021-8979(99)08817-9].