US Patent 7893348 - Vertically oriented Si nanowire array for a solar cell

http://www.freepatentsonline.com/7893348.html

This patent from GE teaches growing an array of silicon nanowires on a substrate to form a doped layer of a p-i-n photovoltaic cell. Claim 1 reads:

1. A photovoltaic device comprising:

a) a plurality of crystalline Si nanowires grown directly on an electrically conductive substrate and disposed in a substantially vertical orientation on the substrate, the Si nanowires having a doping of a first type;

b) a first conformal Si layer of amorphous intrinsic silicon disposed conformally on the plurality of crystalline Si nanowires, such that the first conformal Si layer effectively absorbs a majority of light impinging on the photovoltaic device;

c) a second conformal amorphous Si layer disposed conformally on the first conformal Si layer, the second conformal amorphous Si layer having a doping of a second type, thereby providing for a charge separating junction;

d) a conductive material layer disposed on the second conformal Si layer; and

e) top and bottom contacts operable for connecting the device to an external circuit,

wherein the bottom contact is in electrical contact with the plurality of nanowires and the top contact is in electrical contact with the second conformal Si layer.