EFFECTS OF VERY HIGH HYDROGEN DILUTION AT LOW-TEMPERATURE ON HYDROGENATED AMORPHOUS-SILICON GERMANIUM

The effects of hydrogen dilution of up to 54:1 (= H-2: SiH4) on hydrog enated amorphous silicon germanium (a-SiGe:H) were investigated at sub strate temperatures < 200 degrees C. The photoconductivity (> 10(-5) O mega(-1) cm(-1) and silicon dihydride content (<2 at.%) of a-SiGe:H ca n be maintained with a high hydrogen dilution ratio of 54:1, although these properties deteriorate with our conventional low hydrogen diluti on conditions at a substrate temperature range < 200 degrees C. And th is high-quality a-SiGe:H film was applied to the bottom photovoltaic l ayer of a glass superstrate type a-Si/a-SiGe tandem solar cell submodu le (30 cm x 40 cm), and a stabilized efficiency of 9.5% (light-soaked and measured at Japan Quality Assurance organization (JQA)) was achiev ed. (C) 1998 Elsevier Science B.V. All rights reserved.