Visible and vacuum UV absolute photoresponse of CVD diamond films and correlation with morphology

Some photoconductive devices based on CVD diamond films have been exposed to UV radiation; this paper reports on their performances. The samples have been grown by a Microwave Plasma Enhanced CVD setup. Photoconductors have been produced with ohmic electrodes and both planar and sandwich geometry. The spectral region around the energy gap has been carefully investigated in order to estimate the selectivity of the samples to the UV radiation and the main impurity contributions to conductivity. Furthermore, the quantum efficiency has been measured at some wavelengths in the 120-300 nm range. Finally the overall crystal quality and orientation have been tested by X-ray diffraction. The amount of oriented grains, i.e. the degree of texture, has been estimated and such a parameter related to the photoconductive performances.