OPTICAL AND MECHANICAL-PROPERTIES OF AMORPHOUS CN FILMS

Carbon nitride (CN) films were synthesized on silicon substrates by a combined ion-beam and laser-ablation method, and the variations of the structure, and the optical and the mechanical properties of the CN fi lms were investigated as a function of ion-beam current. All the CN fi lms were amorphous independent of the ion-beam current, and their refr active indices, extinction coefficients and optical band gaps exhibite d a significant dependence on synthesis condition. In particular, the decrease of the refractive indices and the shrinkage of the optical ba nd gap are noticeable as the ion-beam current increases. Also, the har dness of the CN films was found to decrease with ion-beam current. The observed variations of optical and mechanical properties are attribut ed to the changes of the atomic bonding structures which were induced by nitrogen incorporation; reduced interlinking of sp(2) clusters, inc rease in the number and size of sp(2) clusters, and increase of struct ural order in sp(2) clusters. (C) 1997 Elsevier Science S.A.