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Thin films of polyperinaphthalene (PPN) have been obtained by Nd:YAG pulsed laser deposition with a target of perylenetetracarboxylic dianhydride. Components of the films depend on the power and wavelength of the laser light, which is verified by absorption spectra, Raman scattering spectra, and in situ mass spectra. The optimum conditions for the PPN film formation is 10 mJ cm−2 at 266 nm.

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Field emission from closed and open-ended multiwalled nanotubes (MWNTs) was studied by field-emission microscopy. As an application of nanotube field emitters, we manufactured lighting elements with the structure of a triodetype vacuum tube by replacing the conventional thermionic cathodes with the MWNT field emitters. Stable electron emission, adequate luminance and long life of the tubes have been demonstrated.Carbon nanotubes [1] have been attracting considerable attention not only because of their unique physical properties but also because of their applications in composite materials [2] and as elements of electronic devices [3-6] and nanoprobes [7]. Multi-walled nanotubes (MWNTs) [1,8], comprising from 2 to 30 concentric graphitic layers, have outer diameters from 10 to 50 nm, and lengths more than 10 µm. On the other hand, single-walled carbon nanotubes (SWNTs) [9-11] are much thinner, being 1.0 to 1.4 nm in diameter, and of length 100 µm [12]. The high aspect ratio and the small radii of curvature at their tips are realized in carbon nanotubes. The geometric characteristic of nanotubes, together with a high chemical stability and a high mechanical strength [13,14], is advantageous for field emitters. Indeed, field emission (FE) from an individual MWNT [3] and from assemblies of MWNTs [15,16] has been demonstrated. Fieldemission microscopy (FEM) was also performed recently for both MWNT [5] and SWNT [17]. We present here our FEM results obtained for open-ended and closed MWNTs.Based on our study on FE from MWNTs, we have manufactured electron tubes equipped with MWNT field emitters as a cathode. The fabricated tubes (20 mm diameter, 74 mm length) are the three-electrode type, consisting of a cathode (nanotube field emitter arrays), a grid, and an anode (phosphor screen). The manufactured tubes are lighting elements, which are assembled to form a giant outdoor display. Stable electron emission, adequate luminance and long life of the tubes were obtained.

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