Investigation of PbI2 film fabricated by a new sedimentation method as an x-ray conversion material

Radiation detectors are currently fabricated by a screen-print method at room temperature. However, this method has many disadvantages in terms of thickness control and electron trapping. We fabricated polycrystalline PbI2 films by a new sedimentation method and compared the results with those obtained by the existing screen-print (SP) method. We investigated the electrical and structural properties of the films. We fabricated 2x2 cm2 sample films with a thickness of about 200 μm. A field emission scanning electron microscopy (FE-SEM) analysis showed that these films were of higher density than those fabricated by a conventional SP method. We also measured the photosensitivity and dark current of the films. The photosensitivity of the films fabricated by the new sedimentation method was 4.8 pC/(mR·mm2), and the dark current was 2.2 pA/mm2 at 1.0 V/μm. The linearity of the film ranged from 3 to 12 mAs, which is promising for diagnostic radiography. (author)