SEM imaging of insulating specimen through a transparent conducting veil of carbon nanotube

Observing the morphology of insulating specimen in scanning electron microscope (SEM) is of great significance for the nanoscale semiconductor devices and biological tissues. However, the charging effect will cause image distortion and abnormal contrast when observing insulating specimen in SEM. A typical solution to this problem is using metal coating or water-removable conductive coating. Unfortunately, in both cases the surface of the specimen is covered by a thin layer of conductive material which hides the real surface morphology and is very difficult to be completely removed after imaging. Here we show a convenient, residue-free, and versatile method to observe real surface morphology of insulating specimen without charging effect in SEM with the help of a nanometer-thick film of super-aligned carbon nanotube (SACNT). This thin layer of SACNT film, like metal, can conduct the surface charge on insulating specimen through the sample stage to the ground, thus eliminating the charging effect. SACNT film can also be used as the conductive tape to carry and immobilize insulating powder or particles during SEM imaging. Different from the metal coating, SACNT film is transparent, so that the real microstructure of the insulating specimen surface can be observed. In addition, SACNT film can be easily attached to and peeled off from the surface of specimen without any residue. This convenient, residue-free, and versatile method can open up new possibilities in nondestructive SEM imaging of a wide variety of insulating materials, semiconductor devices, and biological tissues.

Automated summary

Observing the real surface morphology of insulating specimen in SEM without charging effect is of great significance. This study presents a convenient, residue-free, and versatile method using a nanometer-thick film of super-aligned carbon nanotube (SACNT) to eliminate the charging effect and allow observation of the real microstructure of the insulating specimen surface.