| 摘要 |
PURPOSE:To obtain a highly efficient photo cell element which shows high photo voltaic effect by forming an active region with super grating structure wherein a multilayer hetero junction alternately laminating two kinds of semiconductor thin films having different forbidden band widths is employed and the potential wells for electron and hole does not exist in the same layer but in the adjacent layer. CONSTITUTION:A photo cell element 1 comprises a super grating structure 6 held by an insulated substrate 2 and an insulating film 4. The insulated substrate 2 can be formed, for example, with a transparent substrate such as glass plate and the insulating film 4 is formed, for example, by a silicon nitride thin film. The super grating structure 6 is formed by semiconductors having different forbidden band widths to that these are parallel to the insulated substrate 2 and the insulating film 4, namely the hetero junction where a thin film (barrier layer) 6a having large forbidden band and a thin film (well layer) 6b having small forbidden band are alternately laminated. The thin films 6a, 6b forming the super grating structure 6 have the thickness of 500Angstrom or less and a number of layers to be laminated is determined so that the total thickness becomes 0.7-1.0mum in the case of amorphous semiconductor or several mum - 300mum in the case of crystal semiconductor. |
