Low-temperature Raman studies of graphene oxide: Analysis of structural properties

This work is devoted to the low-temperature Raman studies of a bright representative of 2D materials-graphene oxide (GO) film in the range of 5-325 K. The performed analysis of the temperature evolution of the peak positions as well as linewidths of two Raman modes D (similar to 1300 cm-1) and G (similar to 1600 cm(-1)) was described in terms of the anharmonic model. The temperature behavior of the G mode demonstrated a slight deviation from the anharmonic model below similar to 50 K in contrast to the D mode, which could be explained by involving an additional phonon decay channel. The analysis of the linewidth of the Raman modes showed that the distribution of defects in GO is inhomogeneous and surface functionalization effectively separates neighboring layers. The average value of the distance between defects and the defect density was estimated. The obtained results can be useful for understanding phonon dynamics for the development of nanodevices based on 2D materials where confinement of propagation of phonon excitations plays a key role.