Abstract: This paper reports diamond-like carbon (DLC) films prepared by using RF (13.56 MHz) plasma enhanced chemical vapor deposition (PECVD) at a lower substrate temperature. The effects of hydrogen dilution, gas pressure and RF power on the properties of the films have been investigated. The structural and optical properties of the DLC films are analyzed by utilizing optical transmission, infrared absorption and small angle X-ray diffraction spectroscopy. The results show that the DLC films are in amorphous state, with a certain amount of C-H bonds. The films with a thickness of about 230nm possess a high transparency, which is more than 83; at 480nm and longer wavelengths in the visible and infrared spectral region, and the deduced Tauc optical band gap is in the range of 2.7eV to 3.7eV. The possibility of using these DLC films as secondary electron emission materials have also been explored.