Direct optical visualization of graphene domains and boundaries assisted by aligned liquid crystal

Abstract

Graphenes produced by CVD open up the application of graphene for novel optoelectonic devices. Properties of polycrystalline graphene are dominated by the size of their domain and direction of domain. various methods such as AFM, SEM, TEM, OM and raman spectroscopy have been used to observe and characterize the property of graphene. Unfortunately, those methods have several drawbacks for practical use such as complicated sample preparation, vacuum environment and damage of graphene during characterizations. More importantly all previous methods are only effective for small area up to several micrometer. Here, we propose new and very simple method to macroscopically visualize the graphene domains and their boundaries assisted by aligned LCs by means of POM. Using this approach, we investigated the effect of domain size and boundary on the quality of graphene in terms of conductance.