Detection and Modeling of Hole Capture by Single Point Defects under Variable Electric Fields

Area of Science:

• Solid-state physics
• Quantum optics
• Materials science

Background:

• Carrier trapping in solids is crucial for semiconductor technologies.
• Previous studies relied on ensembles of point defects, complicating analysis due to neighboring trap interactions and carrier screening.
• Understanding individual trap behavior is essential for advancing quantum technologies.

Purpose of the Study:

• To investigate the capture of photogenerated holes by a single negatively charged nitrogen-vacancy (NV) center in diamond at room temperature.
• To analyze the influence of external electric fields on carrier trapping dynamics at the single-defect level.
• To compare experimental findings with theoretical models for carrier capture mechanisms.

Main Methods:

• Utilized an externally gated potential to control and minimize space-charge effects around the NV center.
• Applied electric fields of variable sign and amplitude to study their impact on hole capture probability.
• Employed semiclassical Monte Carlo simulations to model carrier trapping via phonon emission cascade.
• Correlated experimental measurements with simulation results to validate the trapping model.

Main Results:

• Observed an asymmetric-bell-shaped response in hole capture probability as a function of electric field.
• Found the maximum capture probability occurred at zero applied voltage.
• Achieved good agreement between experimentally measured and simulated electric-field-dependent capture probabilities.
• Demonstrated capture cross sections significantly larger than those typically derived from ensemble measurements.

Conclusions:

• The study provides a detailed understanding of carrier trapping at an individual NV center in diamond.
• The observed electric field asymmetry and large capture cross sections offer insights into single-defect dynamics.
• The underlying trapping mechanisms are likely general and not specific to NV centers, suggesting broader applicability.
• Findings pave the way for improved control over carrier interactions in solid-state quantum systems and novel materials platforms.