Figure 5

The spectra were fit with Voigt functions to extract the peak positions. The total fit is marked in red and original data in blue. Seperate peak fits are plotted as dotted lines with the \(\pi\) plasmon and SP modes marked. A power law was used to model the edge of the zero-loss peak and a linear offset was applied. (a–c). Fits of the \(\pi\) plasmon and SP mode in the Bi₂Se₃ bulk (a), 1 nm from the Bi₂Se₃/SiO₂ interface showing the two peak best fit (b) and at the interface (c), in which the band edge is just visible at 10 eV. (d–f). Fits of the \(\pi\) plasmon mode 1 nm into the Bi₂Se₃ (d) at the Bi₂Se₃/graphene interface (e), and 1 nm into the graphene/aC (f) showing the shift of the \(\pi\) plasmon energy. (g) Plot of G and 2D peak positions measured via Raman on the Bi₂Se₃/graphene flake with the strain (blue) and doping (red) vectors marked. The blue diamonds are the peak positions measured over the flake.