Thickness controlled water vapors assisted growth of multilayer graphene by ambient pressure chemical vapor deposition

Abstract

Chemical vapor deposition graphene growth results are inconsistent, specifying that crucial growth parameters still remain unknown or uncontrolled. In the current study, we demonstrate that water can be used as a special tool to control thickness and size of graphene islands, during ambient pressure chemical vapor deposition growth of graphene. Large area bilayer graphene was synthesized using optimized conditions in the absence of water, which was later used as a reference condition for water assisted growth of multilayer graphene (MLG), by introducing water vapors during the growth stage. Raman spectroscopy, UV-vis spectroscopy, and transmission electron microscopy were used to estimate the quality and thickness of graphene. It was observed that graphene thickness increases from 2 to 25 layers with increase in water vapors ranging from 0 to 2000 ppmv, which revealed significant improvement in growth rate. Scanning electron microscopy results exhibited growth of discontinuous graphene islands which reveal the etching behavior of water vapors. In conclusion, water plays a dual role during growth of graphene, i.e. speeding up growth rate, subsequently resulting in MLG growth, as well as etching of graphene edges.