Temperature-dependent spontaneous emission of PbS quantum dots inside photonic nanostructures at telecommunication wavelength

Abstract

Spontaneous emission of PbS quantum dots (QDs) in different photonic nanostructures has been studied. We use the temperature-dependent exciton photoluminescence and the classic dipole near interface models to understand the spontaneous emission control at various temperatures. Then, we demonstrate that the enhancement and the inhibition of PbS QDs due to the local density of states (LDOS) inside nanostructures are more efficient at temperature as low as 77K than the inhibition at 300K. Largest emission rate enhancement at 77K of 1.67±0.10 and inhibition factors at 100K of 2.27±0.15 are reported for the gold (Au) planar mirror and silicon (Si) two-dimensional photonic crystal bandgap, respectively. We attribute those enhancement and inhibition to the large quantum yields Qe at low temperatures, which is much larger than that at 300K. These results are relevant for application and optimization of PbS QDs in nanophotonics at telecommunication wavelength.