RECENT RESULTS IN SILICON-CNT PHOTODETECTORS

It has been demonstrated from various authors that a Si-Carbon Nanotube heterojunction can be obtained by growing Multi Wall Carbon nanotubes (MWCNT) over a silicon substrate. The electron transport characteristics of hybrid Si-CNT structures have been also largely investigated. Among the wide spectrum of nanotube characteristics, an important rule is determined by their capability to absorb light quanta creating a couple electron-hole that can be separated applying an external electric field. A few mm(2) nanotube layers contains an extremely large number of active elements that can convert incident light into electrons and generate an electrical signal both in case of pulsed light and of continuous radiation. This opens the way to the use of MWCNT for realizing a new kind of radiation detector to be used both for high energy and spatial physics and for sensor applications. In this paper we report on a new detector device realized using MWCNT growth over a silicon substrate. This device presents peculiar characteristics, low noise, good conversion efficiency of photons into electrical current and good signal linearity in a wide range of radiation wavelength from UV to IR at room temperature. The spectral behaviour reflects the silicon spectral range with a maximum at about 880 nm.