THIN-FILM PHOTOVOLTAIC DEVICE AND FABRICATION METHOD

摘要

A method to fabricate thin-film photovoltaic devices (100) comprising a photovoltaic Cu(In,Ga)Se2 or equivalent ABC absorber layer (130), such as an ABC2 layer, deposited onto a back-contact layer (120) characterized in that said method comprises at least five deposition steps, wherein the pair of third and fourth steps are sequentially repeatable, in the presence of at least one C element over one or more steps. In the first step at least one B element is deposited, followed in the second by deposition of A and B elements at a deposition rate ratio Ar/Br, in the third at a ratio Ar/Br lower than the previous, in the fourth at a ratio Ar/Br higher than the previous, and in the fifth depositing only B elements to achieve a final ratio A/B of total deposited elements. The resulting photovoltaic devices are characterized in that, starting from the light-exposed side, the absorber layer (130) of the photovoltaic devices (100) comprises a first region (501) of decreasing Ga / (Ga + In) ratio, followed by a second region (502) of increasing Ga / (Ga + In) ratio where over the light- exposed half side of the second region (502) the value of Ga / (Ga + In) increases by less than 0.15 and contains at least one hump.