Electrical measurements of iodine doped amorphous diamondlike films grown on silicon substrate

By incorporating iodine gas during the films' deposition, amorphous diamondlike carbon (a:DLC) films were doped and a:I-DLC films were obtained. Optical measurements showed that iodine affects the optical band gap, decrease it from 1.1 to 0.78 ev. Iodine doping decreased the resistivity by four orders of magnitude, from 10(8) to 10(4) Omega cm. Iodine doped film was found to have a larger p doping than a:DLC films. the I-V characteristics of devices made of doped and undoped films grown on silicon substrates, were studied, ac measurements of these devices have shown that the p doped a:DLC films behave as semiconductors, and give a rectification with n-type silicon. (C) 1996 American Institute of Physics.