X-Ray Imaging Sensor Using a Polycrystalline Cadmium Telluride-Hydrogenated Amorphous Silicon Heterojunction

Polycrystalline cadmium telluride (pc-CdTe) was prepared by sputtering deposition and was of the zincblende type with a preferential orientation of the (111) planes parallel to the substrate. Its electrical resistivity was 1010 ohm cm and X-ray absorption coefficient was 3×103 cm-1. pc-CdTe formed a good heterojunctin against the hydrogenated amorphous silicon (a-Si:H) prepared by GD-CVD. An X-ray image sensor constructed of the heterojunction showed high sensitivity and high resolution.