A method of synthesis of graphene can include: depositing a carbon (C) layer on a substrate, for example a substrate comprising a silicon (Si) layer and an oxide (SiO2) layer on the Si layer; depositing a metal layer on the C layer; preparing the substrate including the C layer and the metal layer in a chamber; maintaining a pressure of the chamber under 1 atm, for example under 1 Torr; flowing an inert gas in the chamber; contacting a thermal probe tip on the metal layer; heating the thermal probe tip to a temperature of more than 250° C. such that graphene is formed on the substrate; and etching the substrate. The metal layer can be a tin layer.