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US 4,728,370 AGranted
Amorphous photovoltaic elements
AssigneeSumitomo Electric Industries, Ltd.
InventorsMasayuki Ishii, Nobuhiko Fujita, Hajime Hitotsuyanagi
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AssigneeSumitomo Electric Industries, Ltd.
InventorsMasayuki Ishii, Nobuhiko Fujita, Hajime Hitotsuyanagi
Estimating the term…
Disclosed are pin or nip type amorphous photovoltaic elements having the i-type layer comprised of an a-SiGe: H film, which are characterized in that an i-type amorphous silicon buffer layer is disposed between the layers of p-type and i-type and thus, the mutual diffusion of impurities and/or elements added to the i-type and/or the p-type layers through the p/i boundary is effectively restricted due to the presence of the buffer layer. As a result the formation of defects at the p/i boundary and the deterioration of the p-type layer are effectively prevented, and the properties important to these kinds of devices, such as Voc, Jsc, FF being substantially improved, thereby making it possible to provide photovoltaic elements such as solar batteries having a practically acceptable long life span and a high reliability.
A photovoltaic element of pin type structure comprising a pair of electrodes and an amorphous silicon body sandwiched between the pair of electrodes, the amorphous silicon body including a p-type amorphous silicon layer, an i-type amorphous silicon germanium layer, and an n-type amorphous silicon layer laminated in the named order, characterized in that an i-type amorphous silicon buffer layer having a thickness of 100 to 500 angstroms is disposed between the p-type layer and the i-type layer, and in that germanium is added to the portion of the buffer layer at the side adjacent to the i-type over a thickness of from 50 to 150 angstroms, said portion having a germanium concentration gradient which gradually increases towards the i-type layer.
Dependencies are inferred from the claim text.