Deep-Level Structure of the Spin-Active Recombination Center in Dilute Nitrides

Area of Science:

• Semiconductor Physics
• Materials Science
• Quantum Chemistry

Background:

• Gallium interstitial defects are implicated in spin-dependent recombination in GaAsN dilute nitrides.
• These defects are associated with at least two in-gap electronic levels for (+/0) and (++/+) charge transitions.

Purpose of the Study:

• To investigate the in-gap electronic structure of GaAsN dilute nitrides using spin-sensitive techniques.
• To characterize the energy levels of gallium interstitial defects and their charge states.

Main Methods:

• Spin-sensitive photoinduced current transient spectroscopy (SPCTS) was employed.
• The study focused on a GaAs_{1-x}N_{x} alloy with x=0.021.

Main Results:

• The (+/0) charge state transition was located approximately 0.27 eV below the conduction band edge.
• Anomalous negative activation energy indicated the presence of additional in-gap states.
• The (++/+) state was found approximately 0.19 eV above the valence band edge, and a (+++/++) state approximately 25 meV above the valence band edge.

Conclusions:

• The electronic structure of the gallium interstitial defect in GaAsN is more complex than previously thought, involving multiple in-gap states.
• The findings provide a more detailed understanding of the defect responsible for spin-dependent recombination in these materials.