Effect of Structure on the Secondary Electron Emission of Tetrahedral Amorphous Carbon Films

Abstract Tetrahedral amorphous carbon (ta-C) films are appealing for electronic device due to its unique electronic and optical properties. In this work, ta-C films were prepared by filtered cathodic vacuum arc (FCVA) method which is developed by adopting a focusing-deflection system for adjusting the ion beam current density and increasing the deposition field size. The surface morphology of ta-C films prepared by this developed FCVA was presented by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results reveal that the roughness of these ta-C films is only ∼0.4 nm and bias voltages almost unaffected to the surface morphology of the films. Moreover, secondary electron emission properties of ta-C films were investigated with various bias voltages. Compared with bare stainless steel substrate, the secondary electron yield (SEY) of ta-C films decreases significantly. Furthermore, the films deposited at the bias voltages in the range of 110-155V possess the highest maximum secondary electron emission coefficient (δmax) compared to others, which matches well with the variation of sp3content in the films from Raman spectra analyses. These results indicate that the SEY can be tailored by the sp3/sp2 ratio of ta-C films.