Nonexponential photoluminescence transients in a Ga(NAsP) lattice matched to a (001) silicon substrate

Ga(NAsP) grown lattice-matched on (001) silicon substrate is a very promising material for future integrated, electrically pumped lasers on silicon. Here, we present experimental and theoretical studies of the time-resolved photoluminescence in Ga(NAsP)/Si quantum well structures. The experimental results obtained at 10 K show a strong nonexponential transient behavior for the photoluminescence signal. A detailed comparison with theoretical calculations based on rate equations and on straightforward Monte Carlo simulations reveals that this effect is controlled by an interplay between the fast capture of carriers on nonradiative centers and the slow radiative recombination via localized states. We demonstrate that the measurement of the time-resolved photoluminescence can serve as a convenient tool for estimating the relative concentrations of nonradiative and radiative centers in compound materials.