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Silicide formation is strongly affected by the presence of oxygen contained in the metal film. A study has been performed by heating at various times and temperatures samples constituted by a thin Pt film sputter deposited on a silicon substrate. Four different oxygen concentrations were implanted in the Pt film ranging from 1 to 0.1 at.%. The presence of oxygen slows down the growth rate of Pt2Si. At 315 °C in the sample with an oxygen concentration of 1 at.%, about 1000 A of Pt2Si are formed after 20 min of annealing. During the silicide formation, the oxygen originally contained in the platinum films segregates at the Pt2Si/Pt interface. This accumulation acts as a barrier for the transport of Pt and a new phase, PtSi, can form at the Pt2Si/Si interface. The dose necessary to stop the Pt2Si reaction is about (2–4)×1015 at./cm2 at 315 °C.

Recent progress on the development of a new solid state detector allowed the use of finely pixelled photocathodes obtained from silicon semiconductors. SiPM detectors seem to be an ideal tool for the detection of Cherenkov and fluorescence light in spite of their not yet resolved criticism for operating temperature and intrinsic noise. The main disadvantage of SiPM in this case is the poor sensitivity in the wavelength range 300-400 nm, where the Cherenkov light and fluorescence radiation are generated. We report on the possibility to realize a new kind of pixelled photodetector based on the use of silicon substrate with carbon nanotube compounds, more sensitive to the near UV radiation. Also if at the very beginning, the development of such detector appears very promising and useful for astroparticle physics, both in the ground based arrays and in the space experiments. The detectors are ready to be operated in conditions of measurements without signal amplification.