Polycrystalline CdZnTe thick films for low energy x-ray: system evaluation

Area of Science:

• Materials Science
• Solid-State Physics
• Medical Imaging Technology

Background:

• Cadmium Zinc Telluride (CdZnTe) is a promising material for solid-state X-ray detectors.
• Research has primarily focused on single-crystal CdZnTe, limiting applications in large-area detectors for radiography and mammography.
• Large-area detectors require alternative CdZnTe fabrication methods.

Purpose of the Study:

• To develop and characterize thick, polycrystalline CdZnTe films for large-area X-ray detector applications.
• To evaluate the signal-to-noise (S/N) performance of polycrystalline CdZnTe detectors.
• To assess the suitability of polycrystalline CdZnTe as an alternative to single-crystal CdZnTe for advanced X-ray imaging.

Main Methods:

• High-resistivity (>5 x 10^9 Ohm cm) polycrystalline CdZnTe films were grown using thermal evaporation on a carbon substrate.
• A planar detector (32 mm x 10 mm) with a Cd1-xZnxTe (x=0.04) active layer, gold electrodes, and a thickness of 150 micrometers was fabricated.
• X-ray response was measured using signal-to-noise (S/N) analysis and imaging with a data acquisition system.

Main Results:

• Thick, high-resistivity polycrystalline CdZnTe films were successfully grown on a carbon substrate.
• The X-ray detector exhibited a high signal-to-noise ratio, crucial for image quality.
• Images were successfully obtained, demonstrating the detector's functionality.

Conclusions:

• Polycrystalline CdZnTe films offer a viable alternative to single-crystal CdZnTe for large-area X-ray detector applications.
• The developed material and detector design show potential for improving radiography and mammography imaging.
• High S/N performance is achievable with polycrystalline CdZnTe, impacting key imaging parameters like dynamic range and detective quantum efficiency.