Local measurement of secondary electron emission from ZnO-coated carbon nanotubes.

The secondary electron emission (SEE) of ZnO-coated carbon nanotubes (CNTs) was measured using a biasing technique in a scanning electron microscope. The SEE yield of the ZnO-coated CNTs is higher than that of the ZnO film deposited on Si substrates. Direct observation of the variation in SEE from tip-end and non-CNT positions was demonstrated. Local measurement reveals that the SEE yield at the tip-end of the ZnO-coated CNTs is much higher than that of non-CNT positions. The enhancement of SEE is attributed to the strong local field generated at the tip of the CNTs.