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Published on: November 1, 2013
Vertical ordering and electronic coupling in bilayer nanoscale InAs/GaAs quantum dots separated by a thin spacer
S Chakrabarti1, N Halder, S Sengupta
1Center for Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India.
Nanotechnology
|November 28, 2009
Summary
Vertical ordering and electronic coupling in bilayer Indium Arsenide/Gallium Arsenide (InAs/GaAs) quantum dots were studied. Higher coverage reduced ordering and increased tunneling-assisted carrier transfer between dot layers.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Bilayer quantum dots offer unique electronic properties.
- Understanding vertical ordering is crucial for device applications.
- Indium Arsenide/Gallium Arsenide (InAs/GaAs) systems are key for optoelectronics.
Purpose of the Study:
- Investigate vertical ordering and electronic coupling in InAs/GaAs quantum dot bilayers.
- Analyze the impact of spacer layer thickness on dot arrangement.
- Determine the influence of growth parameters on dot ordering and coupling.
Main Methods:
- Transmission Electron Microscopy (TEM) for structural analysis.
- Photoluminescence (PL) spectroscopy for electronic coupling.
- Molecular Beam Epitaxy (MBE) for controlled dot growth.
Main Results:
- Thin spacer layers (7-9 nm) were used.
- Higher monolayer coverages led to reduced vertical ordering due to local strain.
- Increased monolayer coverage correlated with enhanced tunneling-assisted carrier transfer between dot layers.
Conclusions:
- Vertical ordering in InAs/GaAs quantum dot bilayers is sensitive to growth conditions.
- Strain effects at higher coverages disrupt ordering.
- Tunneling-assisted carrier transfer is influenced by dot layer coverage and ordering.
