Carbon Nanotube: New Approach as an Electron Gun

Since the discovery of carbon nanotube (CNT) by Iijima in 1991, several research works have been conducted onto their useful properties, synthesis methods and applications in various fields as well. Because of various unique properties, CNTs are considered as promising field-emission electron sources in scanning electron microscope (SEM), field-emission flat panel displays, X-ray sources, and ideal probe for scanning probe microscopy. We have developed MWCNT field emitter as an electron source for a microcolumn-based FE-SEM. The operating tip bias is much lower while the sample current is higher, compared with those reported for W-tips. Our result suggests that MWCNTs can be considered a promising candidate as an electron source for microcolumn (mini-SEM). We have fabricated several CNT probes (MWCNT probe, DWCNT probe and Pt. ball probe) using a nanomanipulator installed in FE-SEM for AFM and CD-AFM. The nanomanipulator allows a precise control of the length and the alignment of the CNT as well. DWCNT probe and Pt. ball probe were used to image the sidewall roughness of the steep surfaces and compared with other probes.