Ultrasensitive dynamic ultraviolet imaging based on a Ga₂O₃ photodetector array.

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Gallium Oxide (Ga2O3) detectors face limitations due to defects and noise.
• Oxygen vacancies are a primary source of noise in Ga2O3 devices.
• Existing Ga2O3 detectors struggle with practical applications requiring high sensitivity and low noise.

Purpose of the Study:

• To suppress oxygen vacancies in Ga2O3 detectors by optimizing fabrication parameters.
• To investigate the impact of reduced triethylgallium (TEG) flow on detector noise characteristics.
• To develop high-performance Ga2O3-based photodetector arrays for solar-blind UV imaging.

Main Methods:

• Systematically reduced triethylgallium (TEG) flow during Ga2O3 growth from 200 sccm to 50 sccm.
• Characterized noise current, transitioning from Lorentzian to flicker-type noise.
• Measured detector performance metrics including sensitivity and response time.

Main Results:

• Successfully suppressed oxygen vacancies by reducing TEG flow.
• Decreased noise current from 0.15 nA to 1.01 pA, a significant reduction.
• Achieved high sensitivity (3.72 A/W) and fast response times (1.6/13 ms).
• Demonstrated solar-blind detection capabilities with the improved Ga2O3 detectors.

Conclusions:

• Optimized TEG flow is crucial for mitigating noise in Ga2O3 detectors.
• The low-noise Ga2O3 detectors enable advanced UV imaging applications.
• Developed an 8x8 photodetector array capable of real-time UV detection and imaging up to 3 meters.