研究目的
Investigating the effect of GaAs host matrix on excitonic behaviour in AP-MOVPE grown GaSb/GaAs quantum dots (QDs) and achieving room temperature (RT) photoluminescence (PL) emission from single layers of quantum dots by controlling the GaAs host matrix growth temperature.
研究成果
The study demonstrated that increasing the growth temperature of the GaAs host matrix from 500 °C to 650 °C increases the thermal activation energy for carrier quenching and allows for PL emission up to RT in a single GaSb/GaAs QD layer. The hole localisation energy determined for these samples at RT was approximately 470 meV.
研究不足
The study is limited to the effect of GaAs host matrix growth temperature on the thermal quenching of GaSb/GaAs QD PL. The research does not explore other factors that might influence the optical properties of the QDs.
1：Experimental Design and Method Selection:
The study involved the fabrication of GaSb/GaAs QD samples using a Thomas swan MOVPE system at atmospheric pressure with palladium diffused hydrogen as a carrier gas. Triethylgallium, trimethylantimony and tertiarybutylarsine were used as Ga, Sb and As sources respectively.
2：Sample Selection and Data Sources:
Semi-insulating, 2 degrees off GaAs substrates were used as substrates. Three capped GaSb/GaAs QD samples were prepared with the GaAs host matrix deposited at temperatures of 550 °C, 600 °C and 650 °C.
3：List of Experimental Equipment and Materials:
A Bruker Dimension FastScan SPM was used for morphology investigation. Photoluminescence (PL) spectra were collected using a fully automated Czerny-Turner type monochromator, a Nd:YAG diode-pumped laser (532 nm line) for excitation and a liquid nitrogen cooled Ge diode.
4：Experimental Procedures and Operational Workflow:
The samples were mounted in a closed cycle He cryostat and the luminescence was measured from 10 K to RT.
5：Data Analysis Methods:
The optical quality of GaAs was evaluated by comparing the intensity ratio of e-A line to BE-line. Thermal activation energies for the emission quenching were determined through simulating the integrated PL intensities as a function of temperature.
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