*2.6. SEM Imaging*

Scanning electron microscope (SEM) imaging was carried out at a thin-film laboratory, FE-SEM lab (Field Emission), School of Electrical and Computer Engineering, the University of Tehran. A field-emission cathode in the electron gun of a scanning electron microscope provides narrower probing beams at low as well as high electron energies. This way, the spatial resolution was improved

and the charging and damage to the specimens were minimized. As wood is a nonconductive material, a gold sputtering thickness of 6–8 nm was applied on the surface of specimens prior to SEM imaging.
