EFFECT OF HYDROGEN DILUTION IN SILANE ON LIGHT-INDUCED DEGRADATION OFHYDROGENATED AMORPHOUS-SILICON FILMS FOR SOLAR PHOTOVOLTAIC APPLICATIONS

Hydrogenated amorphous silicon films (a-Si:H) have been deposited by r .f. glow discharge of silane (SiH4) and hydrogen (H-2) gas mixture. Th e hydrogen concentration in the gas mixture and the applied r.f. power density have been varied. The initial photoconductivity (sigma(p)), p hotosensitivity (sigma(p)/sigma(d)), activation energy (E(a)), optical band gap (E(g)), hydrogen concentration, sub band gap absorption, Urb ach energy (E(0)) and defect density of the films have been measured, and the degradation, i.e., the reduction of photoconductivity under AM -I (100 mW/cm(2)) white light, has been studied. Films prepared with 9 5% hydrogen dilution and 60 mW/cm(2) r.f power density show the lowest degradation.