Darby & Darby
Photovoltaic cell
 A photovoltaic cell in accordance with the present invention comprises a transparent substrate, a transparent first electrode layer on the substrate and a first semiconductor layer of P type on the first electrode layer, the first semiconductor layer being approximately 25 to 300 .ANG. in thickness and having activation energy of less than 0.3 eV for generation of positive holes. The above stated cell further comprises a second semiconductor layer of the same conductivity type on the first semiconductor layer, the second semiconductor layer being approximately 100 to 1000 .ANG. in thickness and having activation energy of more than 0.3 eV for generation of positive holes. The above stated cell further comprises a third semiconductor layer of I type on the second semiconductor layer, a fourth semiconductor layer of N type on the third semiconductor layer and a second electrode layer on the fourth semiconductor layer. 
Sanyo Electric Co., Ltd.
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Kazuyuki Masaru Takeo
Goto Takeuchi Fukatsu