Abstract: The optical absorption properties of electron-beam-evaporated α-Si_1-xCo_x films have been atudied. The result shows that the changes of the component x in the films affect the optical absorption in the long wave approaching that of the infrared more sensitively than in the short wave; the sensitive region of the optical absorption is in the 0.10 at% < x < 2.00 at% region. In the investigated components, when the component a; increases, the optical band gap of the film narrows from 1.50 eV to 1.28 eV. The experimental result is analysed and discussed with Cody's disorder theory of a-Si film.

Key words: optical absorption, transition element, α-Si film, optical band gap