研究目的
Investigating the optical properties of GaAs/GaAs0.92Sb0.08/GaAs coaxial single quantum-well nanowires, focusing on their power-dependent and temperature-dependent photoluminescence to understand the dynamics of the quasi-type-II quantum well in nanowires.
研究成果
The study demonstrates that GaAs/GaAs0.92Sb0.08/GaAs coaxial single quantum-well nanowires exhibit a quasi-type-II band alignment with both type-I like and type-II like behaviors. The small conduction band offset allows electrons to overcome the barrier with thermal energy, leading to type-II like recombination. This understanding of the dynamics of quasi-type-II quantum wells in nanowires can benefit the development of nanoscale quantum well devices.
研究不足
The study focuses on a specific composition of GaAsSb (GaAs0.92Sb0.08) and may not cover the full range of Sb compositions. The inhomogeneity of Sb content in quantum wells could affect the uniformity of the optical properties.
1:Experimental Design and Method Selection:
The study used molecular beam epitaxy (MBE) to grow GaAs/GaAs
2:92Sb08/GaAs coaxial single quantum-well nanowires. The optical properties were investigated using photoluminescence (PL) spectroscopy at various excitation intensities and temperatures. Sample Selection and Data Sources:
Nanowires were grown on a Si (111) substrate using the Ga-assisted self-catalyzed method.
3:List of Experimental Equipment and Materials:
A DCA P600 solid source MBE system was used for growth. SEM (Hitachi S-4800) and HAADF-STEM (FEI Talos F200X) with EDX (EDAX) were used for morphological characterization. A 655 nm semiconductor diode laser was used for PL measurements.
4:Experimental Procedures and Operational Workflow:
The growth process involved depositing Ga droplets on Si substrates, growing GaAs core, GaAsSb shell, and GaAs cap layer. PL measurements were conducted at different temperatures and excitation powers.
5:Data Analysis Methods:
The PL spectra were analyzed using Gaussian peaks fitting. The temperature dependence of the bandgap was described by the Varshni model.
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