Patent ID: 8829336

Claim:
A photovoltaic device comprising: a substrate comprising an n type layer formed on the substrate; a first structure formed on the n type layer; a second structure stacked on the first structure, wherein the first structure comprises an intrinsic layer on the n type layer and a p type layer on the intrinsic layer and an intrinsic layer on the p type layer and an n type layer on the intrinsic layer and wherein the second structure comprises an intrinsic layer on the n type layer and a p type layer on the intrinsic layer and an intrinsic layer on the p type layer and an n type layer on the intrinsic layer; an array of quantum dots and quantum dashes in the intrinsic layer of the structures; a first groove which extends from a surface of the second structure into the substrate; a second groove parallel to the first groove which extends from the surface of the second structure into the substrate; an n type region in the layers of the first structure, second structure, n type layer adjacent the substrate, and the substrate adjacent the first groove a p type region in the layers of the first structure, second structure, n type layer adjacent the substrate, and the substrate adjacent the second groove; a conductive contact on the portion of the surface of the second structure adjacent the first groove and along the n type region in the first groove; and a conductive contact on a portion of the surface of the second structure adjacent the second groove and along the p type region in the second groove, such that the conductive contact in the first groove is ohmic to the n type layers and rectifying to the p type layers adjacent the first groove and the conductive contact in the second groove is ohmic to the p type layers and rectifying to the n type layers adjacent the second groove.