HYDROGEN-FREE AMORPHOUS-CARBON PREPARATION AND PROPERTIES

Amorphous carbon containing very little hydrogen and having a highly tetrahedral character is deposited by filtered cathodic arc. This amorphous carbon shows photoconductivity under white light illumination. It is slightly p-type in pure form but becomes n-type when doped with nitrogen. Electron diffraction shows that nitrogen levels of less than 1% do not distort the tetrahedral network, but at higher concentrations nitrogen destabilises the tetrahedral structure. Plasmon spectroscopy shows the presence of a 1 nm ''defective'' surface layer even in the pure material which has implications for device applications. A junction field effect transistor structure is proposed as a possible device.