A quantum model of charge capture and release onto/from deep traps

Area of Science:

• Materials Science
• Solid State Physics
• Quantum Mechanics

Background:

• Point defects critically impact optical device performance.
• Thermoluminescence is key for studying defect-induced charge capture and recombination.
• Existing semi-classical models lack quantum mechanical rigor, limiting material extrapolation.

Purpose of the Study:

• Develop a reliable analytical model for non-radiative electron capture and release from the conduction band (CB).
• Incorporate quantum principles like Bose-Einstein statistics and Fermi's golden rule.
• Provide a physically interpretable model for capture coefficients and frequency factors, including trap charge states.

Main Methods:

• Governed by Bose-Einstein statistics for phonon occupation.
• Utilizes Fermi's golden rule for resonant charge transfer.
• Analyzes electron capture/release dynamics between trap states and the conduction band.

Main Results:

• The model physically interprets capture coefficients and frequency factors, linking them to wavefunction overlap and bond ionicity/covalency.
• Demonstrates that capture cross-section is not necessarily dependent on trap depth.
• Shows good agreement with experimental data, validating the model's predictions.

Conclusions:

• The proposed quantum model offers a more accurate description of electron capture and release processes.
• Enables systematic materials research by providing reliable information on trap states.
• Overcomes limitations of semi-classical models for inter-material extrapolation.