Temperature-induced evolution of strain and doping in an isotopically labeled two-dimensional graphene-C-70 fullerene peapod
Abstract
A two-dimensional peapod (2D-peapod) was engineered by sandwiching C-70 fullerenes between two isotopically labeled graphene single-layers. Raman spectral mapping was used to investigate in-situ the evolution of strain and doping associated with topographic changes of the graphene layers in the temperature range 10-300 K.
The isotope labeling of the top layer with C-13 allowed us following the strain and doping in the bottom and top layer independently. The global behavior of the temperature dependence of the C-12 (bottom) and C-13 (top) graphene layer does not significantly deviates from that of an isotopically labeled graphene double layer.
However, the presence of the C-70 fullerenes give rise to the creation of specific networks of wrinkles in the top graphene layer, which significantly evolve with decreasing temperature. We propose that the C-70 fullerenes adhered to the graphene layers act locally as a mutual mechanical coupler, and govern the local reconstruction of the topography of the 2D-peapod.