Fig. 6
Polarity effect of substrate polarity and in 2-D materials in the red box. a From top to bottom: atomic model, DFT simulated potential fluctuation (meV) map, and the EBSD mapping of the crystalline orientation for Si/1L-graphene/Si (left column), GaAs/1L-graphene/GaAs (middle coloum), and LiF/3L-graphene/LiF (right column), respectively. b Schematics of the polarity effect of 2-D materials and corresponding EBSD mapping for GaN remote homoepitaxy with h-BN and graphene, respectively. Enhancing Ge thin film nucleation through dipole moment from 2D and substrate in the blue box. c 3D DFT simulation of electron density in the graphene/h-BN stack, red arrow denoting the direction of non-zero polarization. SEM images of Ge nucleation on top of graphene, ozone-treated graphene, and h-BN on SiO2/Si substrate and HR-TEM micrograph for Ge grown on graphene/h-BN stacked SiO2/Si substrate. d 3D illustration of Ge nucleation on graphene/TiN-AlN hyperbolic metamaterial stack and corresponding SEM image of the Ge surface. e Tilted SEM, low-magnification BF-TEM image and HRTEM at the ZnO/1L-MoS2/ZnO interface. f DFT calculated charge density distribution from both side and top projections