Amorphous-silicon m.i.s. solar cells

M.I.S. solar cells of amorphous silicon on stainless steel, with a top barrier contact of Ni/TiOx, have given 4.8% power conversion efficiency without an antireflection coating. The insulating layer, with an optimum thickness of ¿¿ 2nm, compensates for the low work function of nickel compared with platinum, and enables similar high open-circuit voltages (up to 680 mV) to be obtained. The fill factor is not appreciably degraded by the addition of an insulating layer, unless this is thicker than = 3 nm. Under illumination, the diode characteristics change compared with their behaviour in the dark; the diode factor, the barrier height, and the series resistance are all dependent on light intensity.