Final Report Summary - MESCD (Tuning of the mechanical and electronic properties of graphene by strain, chemical doping and defects)
Graphene and h-BN are two-dimensional materials having several extraordinary physical properties. In order to investigate various physical properties of graphene and h-BN we used elasticity theory, atomistic modeling, density functional theory, and molecular dynamics simulation. We focused mainly on the thermo-electro-mechanical properties of graphene and h-BN.
In particular in this project as was stated in the proposal; i) we focused on the basic and advanced mechanisms of the strain distribution (mostly originated in non-uniform triaxial stress) in two dimensional materials such as graphene and hexagonal boron-nitride (h-BN), ii) we studied the band gap tuning of the mentioned two dimensional materials using different theoretical methods and multi-scale modelling, iii) we investigated the electronic polarization in single/multilayer graphene and h-BN flakes, iv) thermal rippling of hydrogenated/fluorinated graphene was simulated and found to be completely different from that in graphene and h-BN, v) we studied the melting properties of graphene flakes and fluorinated graphene and provided thermo-dynamical phase diagram for fluorinated graphene, i.e. the key factor is the ratio between C and F atoms in fluorinated graphene, vi) we used elasticity theory to explain the ultra-low vibration frequency of freestanding graphene when it is interacting with a scanning tunnelling microscopy tip (work in collaboration with experimental group of P. Thibado of University of Arkansas) and motivated by recent experiments from the Manchester group, vii) the van der Waals energy stored between graphene layer and h-BN substrate has also been studied in this project.
In particular in this project as was stated in the proposal; i) we focused on the basic and advanced mechanisms of the strain distribution (mostly originated in non-uniform triaxial stress) in two dimensional materials such as graphene and hexagonal boron-nitride (h-BN), ii) we studied the band gap tuning of the mentioned two dimensional materials using different theoretical methods and multi-scale modelling, iii) we investigated the electronic polarization in single/multilayer graphene and h-BN flakes, iv) thermal rippling of hydrogenated/fluorinated graphene was simulated and found to be completely different from that in graphene and h-BN, v) we studied the melting properties of graphene flakes and fluorinated graphene and provided thermo-dynamical phase diagram for fluorinated graphene, i.e. the key factor is the ratio between C and F atoms in fluorinated graphene, vi) we used elasticity theory to explain the ultra-low vibration frequency of freestanding graphene when it is interacting with a scanning tunnelling microscopy tip (work in collaboration with experimental group of P. Thibado of University of Arkansas) and motivated by recent experiments from the Manchester group, vii) the van der Waals energy stored between graphene layer and h-BN substrate has also been studied in this project.