Figure 7
Temperature-dependent \(\upmu \)-PL measurements. Spectra shown in the left half of the figure are from the single-layer sample A, those in the right half from the stacked double-QD sample B with a Si spacer width of 2 nm. The temperature range from 10 to 170K is displayed in the upper panels, the range from 190 to 280K in the respective lower panels. Note the different span of the intensity scales of the upper and lower panels. The FE\(_\text{LO/TO}\) signal from the Si substrate and the WL signal in sample A rapidly disappear with increasing temperature. While the intensities of the QD-related signal between 0.8 and 1.0 eV are comparable in both samples, the decay above 190 K is significantly more pronounced in the single-QD-sample A.
