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A new detector of ballistic phonons is presented. It is a P‐doped Si bolometer realized on top of a (100)Si crystal by ion implantation. The open circuit responsivity of the bolometer is 8000 V/W and the response time less than 50 ns. Time‐resolved spectra of ballistic phonons propagating in the same Si crystal along the 〈100〉 direction are reported.

The properties of carbon nanotubes (CNTs), the new allotropic status of carbon discovered in 1991, have been widely investigated in all possible application field. This new material in fact can be easily obtained chemically by CVD (Chemical Vapour Deposition) as a layer of nanotubes growth on a wide variety of materials. When growth on a silicon surface, CNTs create a semiconductor heterojunction with peculiar photoresponsivity properties. We studied this heterojunction with the purpose to realize a large photocathode with high quantum efficiency in a large wavelength range from UV to IR. Results obtained up to day allowed us to build a new kind of photodetector very cheap, stable and easy to manage. Recently this new device has been proposed as one of candidates for the beam monitor system of SuperB.

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.

The realization of a Silicon Carbon Nanotube heterojuntion opens the door to a new generation of photodetectors (Si-CNT detector) based on the coupling between this two materials. In particular the growth of Multiwall Carbon Nanotubes on the surface of a n-doped silicon substrate results on a Schottky diode junction with precise rectifying characteristics. The obtained device presents a low dark current, high efficiency in the photoresponsivity, high linearity and a wide stability range. The junction barrier is about 3.5 V in reverse polarity with a breakdown limit at more than 100 V. The spectral behavior reflects the silicon spectral range with a maximum at about 880 nm.