Double-Sided Bonding Process Enables X-ray Flat Panel Detectors

Area of Science:

• Materials Science
• Detector Physics
• Solid-State Electronics

Background:

• Metal halide perovskites exhibit promising photoelectric properties for X-ray detection.
• Current challenges include integrating perovskites into large-area pixelated sensors for direct X-ray imaging.

Purpose of the Study:

• To develop a scalable fabrication strategy for large-area perovskite X-ray detector arrays.
• To demonstrate the performance of delta-Cesium Lead Iodide (δ-CsPbI₃) in direct X-ray detection.

Main Methods:

• A double-sided bonding process utilizing van der Waals force was employed.
• A wet film deposition technique bonded a thin-film transistor substrate to a δ-CsPbI₃ wafer.
• Characterization of the freestanding polycrystalline δ-CsPbI₃ wafer's X-ray detection performance.

Main Results:

• The fabricated device facilitates area-array imaging for X-ray detection.
• The δ-CsPbI₃ wafer achieved an ultralow detection limit of 3.46 nGy_air s^-1 under 50 kV_P X-ray irradiation.
• Stable signal output was maintained with a signal current drift of 3.5 × 10^-5 pA cm^-1 s^-1 V^-1 under 234.9 mGy_air accumulated dose.

Conclusions:

• The proposed double-sided bonding strategy enables the fabrication of large-area perovskite X-ray detector arrays.
• This method offers a novel approach for the industrial production of perovskite-based X-ray flat panel detectors.
• δ-CsPbI₃ demonstrates excellent stability and sensitivity, paving the way for next-generation X-ray imaging.