Novel Electrodes and Engineered Interfaces for Halide-Semiconductor Radiation Detectors.

Area of Science:

• Materials Science
• Semiconductor Physics
• Radiation Detection Technology

Background:

• Inorganic halide semiconductors are promising for high-efficiency, low-cost radiation detection.
• A major challenge is detector polarization at room temperature, degrading performance and causing device failure.
• Polarization leads to reduced charge collection efficiency and detrimental chemical reactions at metal electrodes.

Purpose of the Study:

• To address the critical challenge of polarization in halide radiation detectors.
• To develop and demonstrate a solution for stable, low-noise spectroscopic detection using Thallium Bromide (TlBr).
• To overcome obstacles hindering the adoption of TlBr as a cost-effective replacement for Cadmium Zinc Telluride (CZT).

Main Methods:

• Application of novel electrodes to Thallium Bromide (TlBr) radiation detectors.
• Fabrication of detectors with virtually defect-free electrode-semiconductor interfaces.
• Testing detector performance under accelerated ageing conditions and extended operational periods.

Main Results:

• Demonstrated continuous, stable detection performance (±1% change in 662 keV gamma channel) for over 4000 hours at room temperature.
• Showcased excellent stability with continuously recorded 137Cs gamma radiation response over 2 months for a pixelated TlBr detector.
• Achieved unprecedented low-noise and stable performance, overcoming major limitations of halide semiconductor detectors.

Conclusions:

• The developed electrode technique effectively eliminates polarization issues in TlBr detectors.
• This innovation provides a pathway for reliable, long-term spectroscopic radiation detection at room temperature.
• TlBr detectors with novel electrodes present a viable, low-cost alternative to CZT detectors.