Catalyst-Free and Large-Area Deposition of Graphitic Carbon Films on Glass Substrates by Pyrolysis of Camphor

The feasibility of obtaining graphitic carbon films on targeted substrates without a catalyst and transfer step was explored through the pyrolysis of the botanical derivative camphor. In a horizontal quartz tube, camphor was subjected to a sequential process of evaporation and thermal decomposition; then, the decomposed product was deposited on a glass substrate. Analysis of the Raman spectra suggest that the deposited film is related to unintentionally doped graphitic carbon containing some $sp-sp^2$ linear carbon chains. The films were transparent in the visible range and electrically conductive, with a sheet resistance comparable to that of graphene. It was also demonstrated that graphitic films with similar properties can be reproduciblyobtained, while property control was readily achieved by varying the process temperature.