InAs/GaInAs(N) quantum dots on GaAs substrate for single photon emitters above 1300 nm

摘要

We demonstrate an optimized molecular beam epitaxial growth procedure of InAs quantum dots (QDs) capped by a low nitrogen content GaInAs(N) quantum well to obtain single QD emission at telecommunication wavelengths. Technical separation of the nitrogen radio frequency plasma source to a second chamber does allow formation of InAs QDs without nitrogen incorporation. Thereby, optical quality degradation is avoided and by additional careful separation of the GaInAsN cap from the InAs QD layer with a partial GaInAs cap of nominal 4 nm thickness we achieve comparatively bright single dot emission above 1300 nm at 8 K. Micro-photoluminescence spectroscopy on single QDs reveal excitonic and biexcitonic emission at 939.8 meV (similar to 1.319 mu m) and 934.6 meV (similar to 1.327 mu m), respectively. Hence, InAs/GaAs(N) QDs can be considered as to be a promising system for use as single photon sources emitting in the 1.3 mu m telecommunication band, with prospects for an extension to even longer wavelengths.