EFFECT OF NEGATIVE RF BIAS ON ELECTROPHOTOGRAPHIC PROPERTIES OF HARD DIAMOND-LIKE CARBON-FILMS DEPOSITED ON ORGANIC PHOTOCONDUCTORS

Hard diamond-like carbon (DLC) films were prepared on organic photocon ductor (OPC) and PMMA (polymethyl methacrylate) samples by electron cy clotron resonance (ECR) CH4-Ar plasma deposition with low substrate bi as. The films exhibited a specific electrical resistivity above 1 x 10 (14) Omega cm and very high transmittance for the visible spectrum of 370-800 nm. The hardness of the OPC samples was increased at least fou rfold after deposition of DLC films. The acceptance voltage, photodisc harge rate and dark decay rate of the DLC-coated OPC samples were all improved, and reached optimal values for rf biases around -90 V. The r esults indicated that the deposition of hard DLC films on OPC is a ver y promising technique to lengthen the working lifetimes of the OPC mat erials.