Doping and Stress Induced Raman Shifts in Pd-Decorated CVD Grown Graphene

Abstract

In this article, we study the interactions of graphene and Pd by using Raman spectroscopy. Graphene grown by chemical vapor deposition (CVD) method was decorated with Pd films with varying thickness ranging from 5 to 25 nm. It has been shown that the positions of both G and 2D peaks in Raman spectra of Pd-graphene (Pd-G) composite are shifted in both sides of the main peaks of graphene and highly dependent on the thickness of the Pd over layer. A blue shift in both G and 2D bands has been observed for lower Pd thickness (≤10 nm). This blue shift is the resultant of the holes doping in graphene due to a work function difference between graphene and Pd. However, strain-induced red shifts in these Raman bands of graphene have been observed for higher Pd thickness (≥15 nm).