Optical energy conversion apparatus

Abstract

An optical energy conversion apparatus 10 includes a first impurity doped semiconductor layer 5 , formed on a substrate, and which is of a semiconductor material admixed with a first impurity, an optically active layer 6 , formed on the first impurity doped semiconductor layer 5 , and which is of a hydrogen-containing amorphous semiconductor material, and a second impurity doped semiconductor layer 7 , admixed with a second impurity and formed on the optically active semiconductor layer 6 . The second impurity doped semiconductor layer is of a polycrystallized semiconductor material lower in hydrogen concentration than the material of the optically active semiconductor layer 6 . The average crystal grain size in the depth-wise direction in an interfacing structure between the optically active semiconductor layer 6 and the second impurity doped semiconductor layer 7 is decreased stepwise in a direction proceeding from the surface of the second impurity doped semiconductor layer towards the substrate 1 . By controlling the hydrogen concentration of the second impurity doped semiconductor layer 7 , the number of dangling bonds in the second impurity doped semiconductor layer 7 is significantly decreased to exhibit superior crystallinity to improve the conversion efficiency of the apparatus 10.

1 - 13 . (canceled)  
     
     
         14 . A method for the preparation of an optical energy conversion apparatus comprising: 
 forming a first impurity doped semiconductor layer on a substrate, said first impurity doped semiconductor layer being of a hydrogen-containing amorphous semiconductor material;    forming an optically active layer on said first impurity doped semiconductor layer, said optically active layer being of a hydrogen-containing amorphous semiconductor material;    forming a second impurity doped semiconductor layer on said optically active layer, said second impurity doped semiconductor layer being of an amorphous semiconductor material which is admixed with a second impurity and which is lower in hydrogen concentration than said optically active layer; and    irradiating laser light on said substrate after forming said second impurity doped semiconductor layer for laser annealing.    
     
     
         15 . The method for the preparation of an optical energy conversion apparatus according to  claim 14  wherein 
 a first electrode layer is formed on said substrate before forming said first impurity doped semiconductor layer on said substrate; and wherein    a second electrode layer is formed on said second impurity doped semiconductor layer after forming said second impurity doped semiconductor layer.    
     
     
         16 . The method for the preparation of an optical energy conversion apparatus according to  claim 14  wherein said first and second impurity doped semiconductor layers are formed by a sputtering device.  
     
     
         17 . The method for the preparation of an optical energy conversion apparatus according to  claim 14  wherein said optically active layer is formed by a sputtering device or by a CVD (chemical vapor deposition) device.  
     
     
         18 . The method of the preparation of an optical energy conversion apparatus according to  claim 14  wherein said second impurity doped semiconductor layer is polycrystallized as the excimer laser is irradiated on a surface thereof.  
     
     
         19 . The method for the preparation of an optical energy conversion apparatus according to  claim 14  wherein the power of the laser light used in a laser annealing is of such a level as to crystallize said second impurity doped semiconductor layer so that the reflection index in case of incidence of light of a wavelength of 200 nm on said second impurity doped semiconductor layer is not less than 50%.