Roughness and optical properties of α-C:H films

α-C:H thin films were deposited by low-pressure plasma enhanced chemical vapor deposition(LPPCVD) with H2 and Trans-2-butene as source gases. Atomic force microscope and scanning electron microscope images demonstrated the surface morphology of the films deposited under different T2B/H2 flow ratios and pressure. It was found that the root-mean-square roughness was 0.97 nm when the T2B/H2 flow ratio and pressure were 4 and 15 Pa respectively. The FTIR spectrum showed that the structure and composition of the films change with the T2B/H2 flow ratios, and this films mainly contain sp3C—H bonds, which have low T2B/H2 flow ratio and possess more C=C bonds. The UV-VIS spectrum showed that the transmission ratios can reach 98% in the visible light range, the films have strong absorption in the