Figure 4
(a) A TEM image of the BLG and TLG flakes after being transferred onto a normal TEM Cu grid. (b) An optical image of the BLG and TLG with the schematic diagram of the crystal orientation determined by Raman spectroscopy. The green and red lines indicate the armchair and zigzag directions, respectively. (c) An HRTEM image of the BLG. The inset of (c) is FFT of (c). The red line connecting the symmetrical pair of dots on the inner circle (corresponding to 0.213 nm spacing) is perpendicular to the zigzag direction of the graphene layers, while the green line connecting the symmetrical pairs of dots on the outer circle (corresponding to 0.123 nm spacing) is perpendicular to the armchair direction of the graphene layers. (d) An atomic-level HRTEM image of the BLG. The inset of (d) shows the line intensity profile of the light blue dotted line. The obtained readings perfectly match the lattice spacing of graphene.
