In our previous study, microstructure and mechanical properties of diamond-like carbon (DLC) films prepared by plasma based ion implantation and deposition using toluene (C₇H₈) as a source gas were investigated. It was reported that G-peak full width at half maximum [FWHM(G)] shows a maximum value at a G-peak position of around 1540 cm^-1, indicating structural changes of DLC films; polymer-like (PLC) to diamond-like carbon (DLC) structure in lower wavenumbers than 1540 cm^-1 and diamond-like to graphite-like carbon (GLC) structure in higher wavenumbers than 1540 cm^-1. Further, two linear relationship between mechanical properties and FWHM(G) were observed depending on the microstructure of DLC films. In this study, we report the dependence of source gases, methane (CH₄), acetylene (C₂H₂) and toluene, on the microstructure of DLC films, and the correlation between microstructure and mechanical properties of DLC films. It was found that FWHM(G) shows a maximum at a G-peak position of around 1540 cm^-1 regardless of source gases. Furthermore, there exists a linear relationship between PL background component and hydrogen content of the films, that is, hydrogen content can be estimated by a simple equation regardless of source gases. The correlation of hardness with FWHM(G) of DLC films prepared using CH₄ and C₂H₂ gas shows good agreement with the correlation line of DLC-GLC provided in the case of C₇H₈.