CVD diamond wires and tips for x-ray detection: growth and characterization by SEM and micro-Raman spectroscopy

摘要

We present a systematic study of the growth of polycrystalline diamond thin films on W wires and tips by hot filament assisted chemical vapor deposition for x-ray detection purposes. We carry out correlations between scanning electron microscopy (SEM) observations and micro-Raman spectra, while varying different growth parameters. SEM observations show a uniform covering of the substrate, with growth rates ranging from 0.5 to 1.5 $mu@m/h. All $mu@-R spectra show a well defined diamond peak at 1330.8-1333.7 cm$+$MIN@1$/ together with abroad structure at 1400-1600 cm$+$MIN@1$/ and a luminescence background extending over the whole scanned range. A close analysis shows that best quality is obtained with the lowest diameter substrates, at the lowest CH$-4$/ concentration and at a low pressure. Some depositions have been studied as x-ray detectors and their sensitivity at low energy and 6 MeV beam evaluated, showing a good response with respect to standard ionization chambers.