Patent ID: 7164150

Claim:
A photovoltaic device comprising: a single crystal semiconductor with impurity doped to establish one conductivity type; a substantially intrinsic amorphous semiconductor thin film formed on and in contact with the single crystal semiconductor having one conductivity type; and an amorphous semiconductor thin film with impurity doped to establish the same or another conductivity type formed on the substantially intrinsic amorphous semiconductor thin film, wherein atoms, which reduce the average coordination number in the substantially intrinsic amorphous semiconductor thin film, exist in the interface formed between the single crystal semiconductor and the substantially intrinsic amorphous semiconductor thin film in a higher concentration than in a bulk, the interface being formed with the substantially intrinsic amorphous semiconductor thin film formed in contact with the single crystal semiconductor, wherein the single crystal semiconductor is a crystalline silicon and the amorphous semiconductor thin film is an amorphous silicon thin film, wherein atoms, which reduce the average coordination number, are oxygen atoms, and wherein a volume concentration of oxygen in the substantially intrinsic amorphous silicon semiconductor thin film is higher than that in the single crystal silicon semiconductor but not higher than 2×10 22 cm −3 , and a surface density of oxygen atoms at the interface is in a range between 5×10 13 cm −2 and 1×10 16 cm −2 .