Direct growth of CdTe thick films on the Medipix2 pixel detector chip.

Polycrystalline CdTe layers were directly deposited on the Medipix2 readout chip by physical vapor deposition using a Riber molecular beam epitaxy 2300. Sb2Te3 was evaporated as backside contact material, resulting in an M-π-p diode structure comprising the pixel contact material, the intentionally undoped CdTe, and Sb2Te3. It was possible to achieve x-ray images at 60 kVp. In addition, thermally oxidized Si wafers were coated with a comparable M-π-p structure grown under identical conditions, to investigate electrical properties of the films. The specific resistance of the layers was found to be 3.85×108 Ω cm. [ABSTRACT FROM AUTHOR]