Tuning of electrical properties of CVD grown graphene by surface doping with organic molecules

Abstract

Tailoring the charge carriers of two-dimensional (2D) materials is essential for high performance optoelectronic devices. The surface transfer doping by adsorption of molecules on 2D crystals is an attractive technique to tune the properties. Here, we study the change in the electronic transport properties of monolayer graphene (MLG) by surface doping with two different types of molecules. An effect of methyl isobutyl ketone (MIBK) and chlorobenzene molecular doping on the carrier concentration and electrical conductivity of chemical vapor deposition(CVD)-grown MLG was carried out by Raman spectroscopy and electrical transport measurement. The shifting of Raman peaks toward higher wave number and shifting of Dirac points toward positive gate voltage confirmed that the surface doping of graphene with MIBK and chlorobenzene molecules induced holes doping effect. The molecular doping approach significantly improved the carrier concentration of CVD grown MLG, which is a promising result. Our study will be useful for understanding as well as improvement of graphene based electronic device research.