Patent ID: 7705235

Claim:
A photovoltaic device, the device comprising: a first layer comprising an amorphous silicon semiconductor material of n-type conductivity; a second layer comprising a crystalline silicon semiconductor material of p-type conductivity; and a third layer comprising a non-doped semiconductor material, wherein the third layer is situated between and contacts the first layer and the second layer, and wherein the third layer is a translucent porous layer and diffusion barrier having a thickness of from about 1 nm to about 50 nm, a fourth layer, wherein the second layer is attached to the fourth layer, wherein the fourth layer comprises a porous layer comprising a fourth semiconductor material, and wherein the fourth semiconductor material comprises non-doped crystalline silicon semiconductor material, a fifth layer, wherein the fourth layer is attached to the fifth layer, wherein the fourth layer and the fifth layer comprise a same conductivity type, and wherein the fifth layer comprises a material selected from the group consisting of amorphous silicon semiconductor material, nanocrystalline semiconductor material, and microcrystalline silicon semiconductor material.