Tuning of mid-infrared emission of ternary PbSrTe/CdTe quantum dots

Tunable room-temperature mid-infrared photoluminescence emission from epitaxial PbSrTe quantum dots embedded in CdTe is demonstrated. By variation of the Sr content, the emission wavelength can be tuned over the whole 3 to 1.6 μm range. Comparing the emission of PbSrTe quantum dots, quantum wells and bulk material, a one order of magnitude increase in the emission efficiency is found for the quantum dots, contrary to the bulk behavior. Theoretical modelling of the transition energies shows that at higher Sr content, segregation of Sr into CdTe occurs. This conclusion is supported by annealing experiments.