In-situ TEM observation of suspended graphene during Joule heating process*

Dynamic surface modification of suspended graphene at high temperature was observed using in-situ transmission electron microscope (TEM) measurement. The suspended graphene were prepared on top of the SiN membrane with hole substrate so that TEM observation was conducted under Joule heating processes. Current-voltage characteristics of suspended graphene devices inside of TEM chamber were measured to monitor and control the high temperature condition of graphene surface by estimating electrical power on the devices. During the in-situ TEM observation, it was found that residual materials, previously remained on the graphene surface, were removed at high temperature. Dynamic movement of residue on the graphene surface and shrinkage of atomic distance of graphene were also observed while the Joule heating process.