2002 年 23 巻 1 号 p. 38-43
Carbon nanotubes (CNTs) possess unique geometrical, electrical, mechanical and chemical properties that make them excellent field emitters. We have investigated the field emission of electrons from CNTs by using field emission microscopy (FEM). In this article, our recent observations of adsorption and desorption of residual gas molecules on clean CNT surfaces and their effects on the emission current are first reported, and then the electron energy distributions are described. Adsorbed gas molecules were observed as bright spots in FEM patterns, giving rise to an abrupt increase in the emission current. The energy spectra clearly exhibited a shoulder at about 500 meV below the main peak, and the full width at half-maximum (FWHM) was about 330 meV. Finally, the methods for preparing CNT cathodes for field emission displays (FEDs) are described and recent development of FEDs with triode-type structures are reviewed.