Amorphous Si Solar cells
Amorphous Photosensors

Amorphous Si Solar cells:

Amorphous Si Solar cells

Solar cells are classified according to the material employed, i.e., crystal silicon, amorphous silicon, and compound semiconductor solar cells “Amorphous” refers to objects having no definite shape and is defined as non-crystal material.
Unlike crystal silicon, in which atomic arrangements are regular, amorphous silicon features irregular atomic arrangements as shown in the figures below. As a result, the reciprocal action between photons and silicon atoms occurs more frequently in amorphous silicon than in crystal silicon, allowing much more light to be absorbed. Thus, an ultra-thin amorphous silicon film of less than 1µm can be produced and used for power generation. Also, by utilizing metal or plastics for the substrate, flexible solar cells can be produced.

Amorton is an integrated amorphous silicon solar cell which has been developed by SANYO. Amorton uses silane (SiH4) as its source gas and is fabricated using a plasma CVD method. Three amorphous silicon layers -- p-layer, i-layer, and n-layer -- are formed consecutively on a glass substrate. This p-i-n junction corresponds to the p/n junction of a crystal silicon solar cell. In the process of this junction formation, a number of cells are connected in series on a substrate at one time. This allows any desired voltage to be obtained for a variety of equipment operation.

Relationship between illumination level and output

The figure shows the relationship between illumination level and output. There is an enormous difference between the illumination levels indoors and outdoors. SANYO provides two types of products, indoor products for use in the low illumination levels common in indoor environments and outdoor products for the high illumination levels common outdoors.

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