On the structure of thin hydrocarbon films

Abstract
We compare reported compositions of a‐C:H films in a ternary phase diagram. It is assumed that the films comprised three phases: sp 3 hybridized carbon,sp 2 hybridized carbon and hydrogen. The data are found to split into two well‐separated groups. This separation depends on the method used to measure the sp 3/sp 2 ratio. We conclude from the comparison of NMR and infrared data that infrared analysis does not provide a quantitative measure of the sp 3/sp 2 ratio.