Figure 2
From: CVD graphene/Ge interface: morphological and electronic characterization of ripples
Characterization of graphene grown on Ge(100) surface. (a) Two-dimensional Raman map of FWHM (2D-band) over an area of 30 × 30 µm2 carried out on every sample; (b) characteristic Raman spectrum of single-layer graphene; (c) the honeycomb structure of graphene/Ge obtained by STM shows the sinusoidal ripples (out-of-plane deformations); (d) STS showed as a (dI/dV)/(I/V) vs V curve, the dotted line indicates the Fermi level (EF), while the blue arrow indicates the position of the Dirac point ED. The tunneling conditions of (c) were V = 25 mV, I = 0.5 nA. The axes inserted in (c) are the specified zigzag (blue arrow) and armchair (green arrow) directions, while X- and Y- scan axes are aligned to the cleavage plane of the Ge substrate, and perpendicular to the main axis of the tip.
