| 摘要 |
PURPOSE:To improve detection efficiency by composing a superconductor layer of at least one layer of a material consisting of a plurality of layers having the different magnitude of energy gaps. CONSTITUTION:With a photosensor 1, a superconductor layer or a semiconductor layer 3 is formed onto a substrate 2, a tunnel barrier layer 4 is shaped onto the surface of the layer 3, and a superconductor layer 5 is formed onto the surface of the layer 4. Sections nearer to the tunnel barrier layer 4 are shaped by a superconductor layer 6 having a small energy gap in the superconductor layer 5 while sections nearer to the outside are formed by a superconductor layer 7 having a large energy gap. Consequently, light projected to the superconductor layer 7 separated from the tunnel barrier layer and having the large energy gap excites electrons in said superconductor layer, and the excited electrons are easy to reach the tunnel barrier layer 4 because they are confined in the superconductor layer 6 having the smaller energy gap on the tunnel barrier layer 4 side by a diffusion. Accordingly, the electrons pass through the tunnel barrier layer 4 by a tunnel effect, and are detected as a current signal.
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