Fig. 2: Characterization of IC-LIG structures on wood: electrical conductivity and Raman spectroscopy.

a, b Optical images of a large-scale (100 cm2) sample of IC-LIG on spruce wood, and c its sheet resistivity map (measured with the contactless eddy-current method; see also Supplementary Fig. 4). d The horizontal line plot at y = 50 mm highlights that the sheet resistivity is constant over a 10 cm distance. e Optical image of the graphitized porous structure and associated Raman map (λ = 532 nm, scale bar 50 µm) of the G-peak (1570–1580 cm−1). f Regions of interest (ROI, −15 × 15 µm2 each) measured at three different positions.