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Suppression of auger processes in confined structures
George E Cragg1, Alexander L Efros
1Naval Research Laboratory, Washington, D.C. 20375, USA. cragg@alum.mit.edu
Nano Letters
|December 19, 2009
Summary
Smoothing the confinement potential significantly reduces nonradiative Auger decay rates for confined carriers. This suggests "magic" nanocrystal sizes exist that strongly suppress these Auger processes, impacting semiconductor device performance.
Area of Science:
- Solid State Physics
- Quantum Mechanics
- Materials Science
Background:
- Nonradiative Auger decay is a critical loss mechanism in semiconductor nanostructures.
- Understanding carrier dynamics is essential for optimizing optoelectronic devices.
Purpose of the Study:
- To investigate the influence of microscopic confinement potential geometry on Auger decay rates.
- To identify design principles for suppressing Auger processes in nanoconfined systems.
Main Methods:
- Utilized the two-band, effective mass Kane model for theoretical calculations.
- Simulated carrier behavior within varying confinement potential shapes and widths.
Main Results:
- Smoothing confinement potentials reduced Auger decay rates by over 3 orders of magnitude.
- Calculated rates exhibited deep minima at specific confinement widths, indicating "magic sizes".
- Abruptly terminating boundaries lead to significantly higher Auger rates.
Conclusions:
- Confinement potential shape is a crucial factor in controlling Auger decay.
- The existence of "magic sizes" offers a pathway to engineer highly efficient nanostructures.
- Findings have implications for designing advanced semiconductor devices with suppressed nonradiative recombination.
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