| abstract |
A composite of a base and an array of needle-like crystals formed on the surface of the base is provided, in which the base side and the opposite side to the base with respect to the array can be isolated in a satisfactory manner. A composite 10 includes a transparent electrode 2 serving as the base, an array 4 of needle-like crystals 3 formed thereon, and a coating film 15 covering the surface of the needle-like crystals 3 . The needle-like crystals 3 are made of, for example, zinc oxide, and the coating film 15 contains, for example, titanium oxide. The array 4 includes a first region R 1 on the transparent electrode 2 side and a second region R 2 on the opposite side to the transparent electrode 2 with respect to the first region R 1 . A proportion of the cross section of the needle-like crystals 3 in a plane parallel to the surface of the transparent electrode 2 is lower in the second region R 2 than in the first region R 1 , and the surface of the transparent electrode 2 is substantially covered with the needle-like crystals 3 in the first region R 1. |