Wide band gap amorphous hydrogenated carbon films grown by plasma enhancedchemical vapor deposition

We have fabricated amorphous hydrogenated carbon films by rf plasma enhance d chemical vapor deposition with very low ion bombardment energy. We demons trate that the optical gap of the films can be tuned in a wide range, from 3.46 up to 4.95 eV, i.e., close to the diamond gap (5.5 eV), by proper cont rol of the negative de self-bias voltage. This behavior suggests that a dra matic reduction in the content and clustering of the sp(2) sites occurs by lowering the ion bombardment energy. (C) 2000 American Vacuum Society. [S07 34-2101(00)01202-1].