IODINE DOPING OF AMORPHOUS DIAMOND-LIKE CARBON-FILMS

Amorphous diamond-like carbon (a:DLC) films have been doped by incorpo ration of iodine during the films deposition. XPS and AES analysis sho ws the existence of iodine atoms with constant concentration of 0.9% a long the iodine doped DLC him (a:I-DLC). The optical and electronic pr operties of the doped films were studied. Optical measurements in the visible light show that iodine affects the interband absorption of the a:DLC films. Iodine causes decreasing of the optical energy gap, from 1.07 to 0.78 eV and affects the density of states at the conducting b and. Like the optical measurements, electrical measurements show that iodine also decreases the activation energy of the films from 0.34 to 0.22 eV. This shows that although both gaps decrease, the optical ener gy gap remains different from that of electrical gap, also after dopin g.