Optical absorption and electrical conductivity of amorphous carbon thin films from camphor: A natural source

Thin films of carbon have been deposited on n-type single-crystal silicon a nd quartz substrates by simple ion beam sputtering of camphoric carbon, obt ained from camphor, a natural source. Optical absorption coefficients of 10 (4)-10(5) cm(-1) have been obtained for the as-deposited and annealed films and the absorption coefficient increased upon annealing. The optical bandg ap energy of the as-deposited camphoric carbon thin film derived from optic al absorption measurements is 0.5 cV. Effects of annealing on various optic al and electrical properties are studied, in light of the semiconducting na ture of these films, through the electrical conduction mechanism. The resul ts obtained are discussed and compared with the literature.