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In/Ga inter-diffusion in InAs quantum dot in InGaAs/GaAs asymmetric quantum well
M H Abdellatif1, Jin Dong Song, Won Jun Choi
1Nano Photonics Research Center Korea Institute of Science and Technology, Seoul 136-791, Korea.
Journal of Nanoscience and Nanotechnology
|September 13, 2012
Summary
This study investigated InAs quantum dots (QDs) in an InGaAs asymmetric quantum well (Asym. QW). Increased Debye temperature due to In/Ga inter-diffusion led to non-radiative defects, causing a rapid PL intensity decrease with rising temperature.
Area of Science:
- Semiconductor Nanostructures
- Quantum Dot Physics
- Materials Science
Background:
- InAs quantum dots (QDs) in InGaAs asymmetric quantum wells (Asym. QWs) are crucial for optoelectronic devices.
- In-atom segregation and In/Ga inter-diffusion significantly influence material properties.
- Understanding thermal effects on QD photoluminescence is vital for device performance.
Purpose of the Study:
- Investigate the temperature and power dependence of photoluminescence (PL) spectra for InAs QDs in an Asym. QW.
- Analyze the impact of In-atom segregation and In/Ga inter-diffusion on thermodynamic parameters, specifically Debye temperature.
- Correlate inter-diffusion-induced defects with the observed changes in PL intensity at varying temperatures.
Main Methods:
- Photoluminescence (PL) spectroscopy was employed to study the ground state emission of InAs QDs.
- Temperature-dependent PL measurements were conducted to assess thermal quenching.
- Power-dependent PL measurements were used to analyze carrier dynamics and defect interactions.
Main Results:
- A higher Debye temperature was observed in the studied QD sample compared to bulk InGaAs, attributed to In/Ga inter-diffusion.
- In/Ga inter-diffusion during growth was identified as the cause of non-radiative defects within the QDs.
- A rapid decrease in the integrated PL emission intensity of the QDs was observed as temperature increased.
Conclusions:
- In/Ga inter-diffusion in InAs QDs within Asym. QWs alters thermodynamic properties like Debye temperature.
- The presence of non-radiative defects, stemming from inter-diffusion, significantly impacts QD emission efficiency.
- Thermal quenching of photoluminescence in these structures is strongly linked to defect-induced non-radiative recombination pathways.
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