Properties of diamond-like films formed by ion-assisted methods for multilayer structures

Abstract

The electrical and optical properties of α-C:H films with different thickness prepared by plasma-ion beam deposition formed from cyclohexen (C 6H 12) vapours and by sputtering of graphite target in Ar,C 6H 12 and their mixtures were investigated. The values of the optical band gap and the resistivity of the films were determined and found to range from 0.6 to 2.0 eV and from 1.0 to 10 8 ω cm respectively. The values strongly depended on the method and deposition conditions as well as on the thickness of the film. The resistivity measurements of the films in the temperature range of 77–300 K show that the jump mechanism of conductivity with variable length of jump along the localized states at the Fermi level with decreasing thickness transforms from three-dimensional to two-dimensional one. It is shown that the multilayer structures formed on the base of α-C:H films have two values of optical band gap corresponding to the values of consisting layers. It might be related to effect of optical absorption quantization in the structures.