Some unusual features in the Raman spectrum of amorphous carbon films obtained by pyrolysis of maleic anhydride

Laser micro-Raman spectroscopic measurements were done on the amorphous conducting carbon films obtained from maleic anhydride by pyrolysis process. We have found a predominant broad peak around 1140 cm−1, in addition to the normally observed peaks in amorphous carbons around 1350 and 1600 cm−1, and peak of medium intensity around 800 cm−1. Here we discuss the possibility of conjugated polymer like bond alternating structure which can give rise to these unusual Raman features