X-ray imaging camera tube using sputter-deposited CdTe/CdSheterojunction

CdTe heterojunction devices have been fabricated for the first time by an RF sputter deposition method for application to X-ray imaging sensors. The electrical resistivities of sputter-deposited polycrystalline CdS and CdTe films are greater than 10⁶ Ω-cm and 10⁹ Ω-cm, respectively. The fabricated CdS/CdTe heterojunction sensor shows a good diode characteristic and a high sensitivity to X-ray radiation. An X-ray imaging camera tube consisting of CdS/CdTe heterojunction photoconductive target shows three times larger responsivity to X-rays than the conventional PbO X-ray tube. The dark current density of the device is observed to be lower than 10 nA/cm² at 20 V target voltage at room temperature