A study of polycristalline CVD diamond by nuclear techniques

The effect of the polycrystalline morphology of CVD diamond on its electronic properties has been investigated by nuclear techniques, essentially by using the sample as a nuclear detector. A particular version of a proton microbeam technique has been used for the first time in order to study the inhomogeneities of carrier transport properties. The data have been correlated with results obtained by other techniques such as SEM, XPS, and EPMA. A good evidence has been gathered for the connection between the grain dimensions and the drift length of carriers in CVD diamond and for the high electric activity of grain boundaries. A model for trapping and recombination at grain boundaries, which could give a crude, but quite general exploration of electronic behaviour of CVD diamond, is presented and discussed. Possible consequences presented on the applications of CVD diamond as a nuclear particle detector and as UV light emitting diode are also briefly described.