| 摘要 |
PURPOSE:To improve the reliability of a photoconductive thin film element as a photosensor by forming an amorphous silicon layer in a layer structure having an i-type (n-type)/P<+>/i (n-type) configuration or P/n<+>/P configuration to generate a triangular barrier of an energy potential to accelerate an optical responding speed and to increase the difference between a bright current and a dark current. CONSTITUTION:An amorphous silicon (a-Si) as a photoconductive thin film is formed in a layer having an a-Si i-type layer (n-type)/P<+> type layer/i-type layer (n-type) configuration or a P-type layer/n<+> type layer/P-type layer configuration reverse thereto in a structure having a triangular barrier of energy potential in the intermediate. For example, a lower electrode 2 is formed of an opaque metal such as Cr on a substrate 1 made of metal or ceramic material, and an n<+> type layer 7 is formed as an ohmic layer thereon. An a-Si i-type layer 31, a P<+> type layer 32 and an a-Si i-type layer 33 are formed in this order thereon, and an n<+> type layer 8 to become an ohmic layer is formed thereon. A transparent SnO2 or ITO laminate is eventually formed as an upper electrode 4. In this configuration, when a light is emitted from above, a photoelectric conversion is executed at high speed.
|
