| 摘要 |
PURPOSE:To select cut-off wavelength continuously at low cost by providing a means through which a substance which has first and second main surfaces, is brought into contact with a substrate on the first main surface and includes a large number of localized levels in a forbidden band is brought into contact with a substance having high conductivity on the second main surface, and voltage is applied between the substrate and the substance having high conductivity. CONSTITUTION:When amorphous silicon 2 is irradiated with infrared beams 8 having energy hupsilon, electrons 4 and holes 5 are generated. Holes having energy larger than an energy barrier phib shaped in the amorphous silicon 2 on the interface of a P-type single crystal silicon substrate 1 and the amorphous silicon 2 are discharged to the P-type single crystal silicon substrate 1 by a tunnel effect by an electric field, and changed into photocurrents (the arrow A). On the other hand, electrons 4 are discharged similarly to a metal 3 (the arrow B), and an empty localized level can be shaped. Cut-off wavelength lambdac is determined by the energy barrier phib, and phib is decided by the work function of the amorphous silicon 2. Accordingly, the energy barrier phib can also be selected within a wide range continuously, thus freely selecting cut-off wavelength lambdac.
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