Indications of amplified spontaneous emission in the energy transfer between InAs self-assembled quantum dots

We have studied the energy-transfer process in InAs self-assembled quantum dots (QD's) for low and high QD density, analyzing the spectral, spot size and excitation intensity dependence of the spatially resolved low-temperature cw microluminescence. We have observed energy transfer from small QD's to larger QD's even outside the excitation region over the sample. An amplified spontaneous emission driven energy-transfer mechanism is used to explain our results.