Influence of CVD diamond film textures on the electrical response of radiation detectors

The influence of the texture of polycrystalline CVD diamond films on their electrical properties was studied. The films were deposited by a microwave-plasma-enhanced chemical vapour deposition technique (MPCVD). 〈110〉 and 〈100〉 textured films, and non-textured films were produced under different growth conditions. Extensive measurements were carried out in order to probe the electrical properties of the films: resistivity, carrier lifetimes, mobility and carrier drift length before trapping. The influence of nitrogen impurities on the film electrical properties is addressed. CVD diamond detectors were characterised electrically in photo-current mode at room temperature under X-ray radiation at 40 keV. The results give evidence of a strong influence of the texture, nitrogen impurities and polycrystalline structural defects of the films on their use as X-ray detectors.