Laser-Etched Array-Patterned Lead Oxide Polycrystalline Thin Film for Direct Conversion Flexible X-ray Detector Application

Lead oxide (PbO) stands out as a highly promising material for direct conversion X-ray detectors owing to its high atomic number of lead (Pb) atoms and significant theoretical photon-to-charge conversion gain. In this work, a kind of flexible X-ray detector utilizing PbO polycrystalline thin films was successfully fabricated through a combination of electron beam evaporation and laser etching array-patterned techniques. The resulting films exhibited an orthorhombic crystal structure and a polycrystalline nature. The array-patterned films offer the advantage of providing cross-talk-free charge signals while also maintaining flexibility and stability. This is achieved by allowing the stress generated during the bending process to be released at the edge of each array, thereby preventing stress accumulation and minimizing the occurrence of cracks in the active region. These devices exhibit extremely low dark current of about 3.4 pA and remarkable photocurrent up to 200 pA under X-ray exposure, as well as the X-ray detection sensitivity of 3.39 × 10 3 μC·Gy –1 cm –2 and signal-to-noise ratio of 204. The acceptable dark current, photocurrent, signal-to-noise ratio, sensitivity, and transient lag behavior were used to assess the flexibility, stability, and uniformity of the devices. The obtained results collectively indicate that PbO thin films have the potential to be used as X-ray-detection materials for flexible applications.