Photo-Excited Carrier Dynamics in Ammonothermal Mn-Compensated GaN Semiconductor

Area of Science:

• Semiconductor Physics
• Materials Science
• Optoelectronics

Background:

• Ammonothermal gallium nitride (GaN:Mn) is a promising semiconductor material.
• Understanding carrier dynamics and defect impacts is crucial for device performance.

Purpose of the Study:

• To investigate carrier dynamics in ammonothermal GaN:Mn using photo-excitation.
• To determine the influence of Mn-induced states and Mg acceptors on charge carrier relaxation rates.

Main Methods:

• Photoluminescence analysis with sub-bandgap and above-bandgap photo-excitation.
• Pump-probe measurements for time-resolved carrier dynamics.
• Contactless probing techniques for defect analysis.

Main Results:

• Mn impurities exhibit photoconductivity and absorption bands around 700-800 nm.
• Electrons in conduction band tails drive photoconductivity and yellow luminescence decays.
• Mg acceptors dominate slower red luminescence and pump-probe decays.
• Yellow photoluminescence decay time increases with excitation intensity due to defect saturation.

Conclusions:

• Carrier relaxation in GaN:Mn is influenced by Mn states and Mg acceptors.
• Fast photo-carrier decay is vital for high-frequency and high-voltage device applications.