Photoluminescence study of biexciton luminescence on the naturally occurring quantum dots in undoped InGaAs/GaAs quantum wells

We report on a photoluminescence study of excitons and biexcitons localized at naturally occurring quantum dots formed due to monolayer well width fluctuations in undoped InGaAs/GaAs quantum wells by macro-photoluminescence measurement. Pseudomorphic InGaAs/GaAs quantum well heterostructures with low indium composition (0.1) were grown by molecular beam epitaxy. At certain positions on the samples, evolution of the spectral features as function of excitation powers shows the formation of biexcitons and their binding energy was found to be of about 3 meV