Patent ID: 8203071

Claim:
A tandem junction photovoltaic device, comprising: a first photovoltaic junction and a second photovoltaic junction, wherein the first photovoltaic junction comprises: a p-type amorphous silicon layer; a p-i buffer intrinsic type amorphous silicon layer; a bulk intrinsic type amorphous silicon layer, wherein the p-i buffer intrinsic type amorphous silicon layer and the bulk intrinsic type amorphous silicon layer are deposited in a single processing chamber by supplying a gas mixture including a silicon containing gas and a hydrogen containing gas, wherein the hydrogen containing gas supplied into the processing chamber is gradually reduced to smoothly transition depositing the p-i buffer intrinsic type amorphous silicon layer to depositing the bulk intrinsic type amorphous silicon layer; and a n-type microcrystalline silicon layer; and wherein the second photovoltaic junction comprises: a p-doped microcrystalline silicon layer; an intrinsic type microcrystalline silicon layer; and a n-doped amorphous silicon layer adjacent to the intrinsic type microcrystalline silicon layer.