Thermal Stability of Defect-Enhanced Ge on Si Quantum Dot Luminescence upon Millisecond Flash Lamp Annealing

The intentional merging of epitaxial Ge on Si(001) quantum dots with optically active defect sites promises low-cost applications such as room temperature (RT)light emitters in Si photonics. Despite recent progress in this field, important benchmarks, for example, the thermal stability of such a combination of low-dimensional nanosystems, as well as the curing of parasitic charge-carrier recombination channels, have been barely investigated thus far. Herein, the structural robustness of defect-enhanced quantum dots (DEQDs) is examined under millisecond flash lamp annealing (FLA), carried out at sample temperatures up to 800oC. Changes in the optical DEQD properties are investigated using photoluminescence spectroscopy performed in a sample temperature range from10 to 300 K. It is demonstrated that FLA—in contrast to in situ thermal annealing—leads to only negligible modifications of the electronic band alignment. Moreover, upon proper conditions of FLA, the RT emission intensity of DEQDs is improved by almost 50% with respect to untreated reference samples.