Observation of Conductive Interstitial Ga Line Defects in β-Ga₂O₃.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Physics

Background:

• Beta-phase gallium sesquioxide (β-Ga₂O₃) is a promising ultrawide bandgap semiconductor for deep-UV optoelectronics and high-power applications.
• Nanometer-scale line defects in β-Ga₂O₃ act as "killer defects", degrading device performance by increasing leakage currents and reducing breakdown voltage.
• The atomic-scale behavior and electrical impact of these defects remain poorly understood.

Purpose of the Study:

• To investigate the nature and properties of atomic-scale line defects in β-Ga₂O₃ nanoflakes.
• To elucidate the impact of these defects on the material's electronic and optical characteristics.
• To explore potential applications of these conductive defects in nanophotonics.

Main Methods:

• Near-field infrared imaging for defect observation at the nanoscale.
• Atomic-resolution imaging techniques.
• Density functional theory (DFT) calculations for defect identification and characterization.

Main Results:

• Observation of novel conductive atomic line defects within β-Ga₂O₃ nanoflakes.
• Identification of these defects as interstitial Gallium (Ga) atoms migrating along the c-axis.
• Demonstration of enhanced local conductivity, broadband infrared response, and quenched cathodoluminescence associated with these defects.

Conclusions:

• Atomic-scale line defects in β-Ga₂O₃ possess distinct and significant conductivity.
• These findings highlight the critical need for managing these defects during material synthesis and device fabrication.
• The unique conductivity of these defects presents opportunities for novel nanophotonic applications.