Hyunjeong Jeong1,Dong Hoon Shin2,Heena Inani3,Kimmo Mustonen3,Clemens Mangler3,Yugyeong Je1,Jani Kotakoski3,Sang Wook Lee1
Ewha Womans University1,Delft University of Technology2,University of Vienna, Vienna3
Hyunjeong Jeong1,Dong Hoon Shin2,Heena Inani3,Kimmo Mustonen3,Clemens Mangler3,Yugyeong Je1,Jani Kotakoski3,Sang Wook Lee1
Ewha Womans University1,Delft University of Technology2,University of Vienna, Vienna3
We investigated <i>in-situ</i> observations of the dynamic changes in graphene by external stimuli such as Joule heating and electron beam irradiation. The carbon structure of graphene was directly observed under electron beam irradiation using a scanning transmission electron microscope (STEM). Suspended graphene was prepared on a Silicon nitride membrane substrate with a hole pattern and connected to electrodes. The Joule heating process by applying a high current can accumulate a high temperature in the middle of the suspended graphene region. In the case of the twisted bilayer graphene structure, the periodicity of the Moiré pattern was changed before and after the Joule heating process. This implies that small flakes of graphene may rotate at high temperature. We also report the observation of defect healing in graphene by electron beam irradiation and the Joule heating process.