1：Experimental Design and Method Selection:

The study uses photoluminescence (PL) spectroscopy to investigate the optical properties of self-assembled GaSb/GaAs quantum dots (QDs) grown on Ge substrates. The methodology includes excitation-power- and temperature-dependent PL measurements to study carrier transfer mechanisms.

2：Sample Selection and Data Sources:

Three samples of GaSb/GaAs QDs were grown on Ge substrates under various growth conditions (samples A-C). For comparison, three samples were also grown on GaAs substrates (samples D-F).

3：List of Experimental Equipment and Materials:

The growth of QDs was performed using solid-source molecular beam epitaxy (MBE Riber compact 21 TM) equipped with an antimony (Sb) valved cracker cell. PL measurements were conducted using a 785 nm laser diode and detected with a liquid-nitrogen-cooled InGaAs detector.

4：Experimental Procedures and Operational Workflow:

After oxide desorption, a 500-nm-thick GaAs buffer layer was grown on a (001) Ge substrate at 550 °C. GaSb QDs were then grown under various conditions, followed by capping with a GaAs layer. AFM was used to characterize surface morphology.

5：Data Analysis Methods:

The PL data were analyzed to determine peak energies, integrated intensities, and thermal activation energies using the Arrhenius relation.