We have manufactured cathode ray tubes (CRTs) equipped with field emitters composed of multiwalled carbon nanotubes. The fabricated CRTs (20 mm in diameter by 74 mm in length) are of a triode type, consisting of a cathode (nanotube field emitter arrays), a grid and an anode (phosphor screen). The manufactured CRTs are lighting elements, which are assembled to form a giant outdoor display. Stable electron emission, adequate luminance and long life are demonstrated. The CRT lighting elements presented here are the first practical products utilizing carbon nanotubes on an industrial scale.

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A bulk bundle (with a diameter of about 100 µ m) of single-walled nanotubes (SWNTs), which were obtained after a purification process of carbon soot containing SWNTs, was used as an electron emitter. Many spikes of micro-bundles (with a typical diameter of 20–30 nm) of SWNTs extruded from the surface of the bulk emitter. Field emission originating from individual micro-bundles was observed on a fluorescent screen 50 mm apart from the tip. Each micro-bundle of SWNTs gave a corresponding bright spot, but no fine structure was observed within the bright spots. A probe hole device was used to measure an electron current from a single micro-bundle. The Fowler-Nordheim plot of the current and the applied voltage yielded a straight line, confirming the current results from field emission.

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Copper phtalocyanine (CuPc) films with the thickness controlled in molecular scales have been grown epitaxially on (0001) surfaces of layered materials, and electronic interaction at the interfaces have been studied by photoelectron spectroscopy. Materials with different electronic properties having different work functions (Evac) were chosen as the substrates; semiconducting MoTe2 (Evac=4.0 eV), semi-metallic highly oriented pyrolytic graphite (Evac=4.5 eV) and metallic TaSe2 (Evac=5.5 eV). Formation of interface dipole layers was found at CuPc/TaSe2 interfaces and molecular orbitals involved were identified.