Photoluminescence on low-temperature grown InAs/GaAs quantum dots

We study low temperature (LT, 250°C) grown Stranski-Krastanov InAs/GaAs quantum dots (QDs) to combine the large QD optical nonlinearity with an ultrafast response time. We observe a QD photoluminescence peak around 1200 nm on top of a background due to the AsGa-VAs center. The QD-emission line disappears with increasing temperature around 30K. The PL-efficiency increases with a factor of 45- 280 as a function of excitation wavelength around the GaAs bandgap. Our observations point towards QDs with good optical quality, embedded in a LT-GaAs barrier in which the carriers are efficiently trapped at anti-site defects