To provide a photocathode and an electron tube capable of detecting light of a comparatively long wavelength and enabled to be manufactured in a simple manufacturing process.
The electron tube 10 is provided with a photocathode 11, a positive electrode 17 and a vacuum vessel 18. The photocathode 11 is provided with a substrate 12, a light absorption layer 14 excited by an incident light to generate photoelectron e2, and an active layer 15 lowering work function of the surface of the light absorption layer 14. The light absorption layer 14 contains carbon nanotube (CNT), and a catalyst layer 13 is provided for growing the CNT between the light absorption layer 14 and the substrate 12. The positive electrode 17 is arranged in opposition to the photocathode 11 to collect photoelectron e2 emitted from the CNT of the light absorption layer 14. An exciting wavelength of the CNT depends on its shape, and a photocathode capable of detecting a long-wavelength incident light L2 of, for instance, a wavelength of not less 1 μm, can be realized in a simple process.
SUGA HIROBUMI
Shiro Terasaki
Satoru Ishida