Patent ID: 7893351

Claim:
A photovoltaic device comprising: crystalline silicon of a first conductivity type; a first amorphous silicon layer of a second conductivity type; and a substantially intrinsic second amorphous silicon layer disposed between the crystalline silicon and the first amorphous silicon layer having a thickness such that light absorbed by the second amorphous silicon layer does not substantially contribute to power generation, the second amorphous silicon layer comprising: a first section located on the crystalline silicon side and having a first oxygen concentration equal to or below 10 20 cm −3 , and a second section located on the first amorphous silicon layer side and having a second oxygen concentration equal to or above 10 20 cm −3 , wherein the oxygen concentration at the junction between the crystalline silicon and the substantially intrinsic second amorphous silicon layer is equal to or below 10 20 cm −3 , wherein the second amorphous silicon layer further comprises a third section that has a third oxygen concentration larger than the first oxygen concentration, and which is located closer to the crystalline silicon than the first section, and in the vicinity of the interface between the crystalline silicon and the second amorphous silicon layer.