Thermal Vibrations Of Graphene Sheets On The Substrate

The discovery of graphene caused a research boom around the world. Graphene is one of thethinnest material and this material is very strong. In this thesis, the thermal vibration ofdouble-layered graphene sheets (DLGS) and graphene on the substrate are studied by using moleculardynamics (MD) method and continuum mechanics. Under the heat excitation, thermal motionproblems of graphene on substrate is also been studied. The main progresses and contributions of thethesis are as follows.Dynamics problems in the thermal vibration of DLGS is studied by using MD method. Thenatural frequency of DLGS with all boundary simply supported is nearly the same at differenttemperature. The gap of the natural frequency of boundary hydrogenated DLGS with one layer fixed,another layer all boundary simply supported between MD simulation and Continuum mechanics isvery small. When the size of DLGS is small, the gap of the natural frequency between DLGS withboundary hydrogenated and DLGS with boundary non-hydrogenated is a little bit large.Dynamics problems in the thermal vibration of single-layered graphene sheets (SLGS) anddouble-layered graphene sheets (DLGS) on gold and silicon substrates are studied by using MDmethod and continuum mechanics. The van der Waals (vdW) interaction coefficients betweengraphene and substrate is been calculated. The gap of natural frequency of SLGS on substratebetween MD simulation and continuum mechanics is small and the vdW force has contributed a lot tothe frequency. The gap between MD simulation and continuum mechanics of natural frequency ofDLGS on substrate is very small.Thermal motion problems of graphene under the under heat excitation on substrate is also beenstudied. When the temperature is higher, graphene on substrate will move over the potential barrier.The graphene has his own orientations when moving.