Comprehensive characterization of different metallic thin films on highly oriented pyrolytic graphite substrate

Abstract

Thin metallic films supported on highly oriented pyrolytic graphite (HOPG) with low surface roughness are needed to improve the performance of different industrial applications and devices. As a result, an experimental investigation of electron beam physical vapour deposition of M (= Ti, Au, and Ag) metals on HOPG substrate to form HOPG-M thin films with a nominal thickness of 10 nm is reported. The comprehensive characterizations of the films were performed using different characterization techniques. The findings show that the films formed had different morphologies and topographies where Ti film was continuous while Au and Ag films were made up of islands with some discontinuities. The surface chemistry shows that the Ti film existed in both metallic and oxidized states while the Au and Ag films existed in metallic states. Raman analysis shows that there were some variations in the molecular structures after deposition while FTIR analysis shows that different functional groups existed on the thin films. The surface wettability behaviour of the Ag film based on water contact angles was hydrophobic while the other samples were hydrophilic. This work provides an opportunity for further examination of the HOPG as a substrate for the preparation of different M thin films.