Structural, optical and electrical properties of amorphous carbon films deposited by pulsed unbalanced magnetron sputtering

Amorphous carbon (a-C) films were deposited by pulsed unbalanced magnetron sputtering method, the effects of substrate temperature on the structure, optical and electrical properties of the a-C films were investigated. It has been found that the sp3 fraction in the a-C films increases with increasing substrate temperature from 50 to 100 °C, while decreases with increasing substrate temperature from 100 to 200 °C. Optical and electrical measurements show that the refractive index, optical band gap and electrical resistivity are strongly dependent on the substrate temperature. The a-C films deposited at 100 °C have higher refractive index, optical band gap and electrical resistivity. The possible reason for all the above observation was discussed. The results above are useful for the practical application of a-C films.