X-ray response characterization of Y2O2S:Tb-CdS layered semiconductor

Phosphors coupled with photodetectors have been widely used in digital X-ray imaging applications. Some of the advantages of using phosphor films include X-ray conversion efficiency, spatial resolution, and integration with the imaging array. In this paper, the experimental studies of the Y₂O₂S:Tb synthesis, deposition, and characterization are reported on. Y₂O₂S:Tb powder was characterized in terms of scanning electron microscopy (SEM), X-ray diffraction (XRD), luminescence spectroscopy, and X-ray conversion efficiency. In addition, a Y₂O₂S:Tb layer was formed on cadmium sulphide (CdS) for the hybrid X-ray detector structure. The evaluation of the Y₂O₂S:Tb-CdS detector was performed by determining the leakage current, X-ray sensitivity, and linearity with respect to X-ray exposure dose. The results of the study made on the two-layered detector are compared with those from a conventional amorphous selenium (a-Se) detector.