Growth and characterization of single quantum dots emitting at 1300 nm

We have optimized the molecular-beam epitaxy growth conditions of self-organized InAsGaAs quantum dots (QDs) to achieve a low density of dots emitting at 1300 nm at low temperature. We used an ultralow InAs growth rate, lower than 0.002 MLs, to reduce the density to 2 dotsμ m2 and an InGaAs capping layer to achieve longer emission wavelength. Microphotoluminescence spectroscopy at low-temperature reveals emission lines characteristic of exciton-biexciton behavior. We also study the temperature dependence of the photoluminescence, showing clear single QD emission up to 90 K. With these results, InAsGaAs QDs appear as a very promising system for future applications of single photon sources in fiber-based quantum cryptography.