A semiconductor structure including a bonding layer connecting a first semiconductor wafer layer to a second semiconductor wafer layer, the bonding layer including an electrically conductive carbonaceous component and a binder component.

A multijunction solar cell including a tandem vertical stack of a least an upper solar subcell, a first middle solar subcell, and bottom solar subcell; a first lateral conduction interlayer disposed adjacent to and beneath the second solar subcell; a blocking p-n diode or insulating layer disposed adjacent to and beneath the first lateral conduction interlayer; and a second lateral conduction layer disposed adjacent to and beneath the blocking p-n diode or insulating layer.

A multijunction solar cell including a tandem vertical stack of a least an upper solar subcell, a first middle solar subcell, and bottom solar subcell; a first lateral conduction interlayer disposed adjacent to and beneath the second solar subcell; a blocking p-n diode or insulating layer disposed adjacent to and beneath the first lateral conduction interlayer; and a second lateral conduction layer disposed adjacent to and beneath the blocking p-n diode or insulating layer.

A method of forming a multijunction solar cell that includes an InGaAs buffer layer and an InGaAlAs grading interlayer disposed below, and adjacent to, the InGaAs buffer layer. The grading interlayer achieves a transition in lattice constant from one solar subcell to another adjacent solar subcell.

A method of forming a multijunction solar cell that includes an InGaAs buffer layer and an InGaAlAs grading interlayer disposed below, and adjacent to, the InGaAs buffer layer. The grading interlayer achieves a transition in lattice constant from one solar subcell to another adjacent solar subcell.

A monocrystalline germanium wafer that increases the open-circuit voltage of multijunction solar cells, a method for preparing the monocrystalline germanium wafer and a method for preparing an ingot from which the monocrystalline germanium wafer is prepared. The monocrystalline germanium wafer that increases the open-circuit voltage of the bottom cell of multijunction solar cells is prepared by adjusting the amounts of the co-dopants silicon and gallium in the monocrystalline germanium wafer, the ratio of silicon to gallium in the preparation of the monocrystalline germanium.

An InGaN solar photovoltaic device includes a base band, a light absorption layer, an n-type ZnO electron transport layer, and a p-type InN hole transport layer, the p-type InN hole transport layer is on a front side of the light absorption layer, and the base band and the n-type ZnO electron transport layer are on a back side of the light absorption layer, wherein the light absorption layer includes a p-type In.sub.xGa.sub.1-XN layer and an n-type In.sub.yGa.sub.1-yN layer which are superposed, where 0.2<x<0.4 and 0.2<y<0.4, and the p-type In.sub.xGa.sub.1-XN layer and the n-type In.sub.yGa.sub.1-yN layer are doped with Si and Mg. The InGaN solar photovoltaic device with a flexible multi-layer structure features high in energy conversion efficiency, low in cost, simple in manufacturing, and easy to implement, and thus has a broad prospect in application.

An InGaN solar photovoltaic device includes a base band, a light absorption layer, an n-type ZnO electron transport layer, and a p-type InN hole transport layer, the p-type InN hole transport layer is on a front side of the light absorption layer, and the base band and the n-type ZnO electron transport layer are on a back side of the light absorption layer, wherein the light absorption layer includes a p-type In.sub.xGa.sub.1-XN layer and an n-type In.sub.yGa.sub.1-yN layer which are superposed, where 0.2<x<0.4 and 0.2<y<0.4, and the p-type In.sub.xGa.sub.1-XN layer and the n-type In.sub.yGa.sub.1-yN layer are doped with Si and Mg. The InGaN solar photovoltaic device with a flexible multi-layer structure features high in energy conversion efficiency, low in cost, simple in manufacturing, and easy to implement, and thus has a broad prospect in application.

A method is described that includes sputtering multiple layers on a back surface of the photovoltaic structure, the photovoltaic structure being made of at least one group III-V semiconductor material, and evaporating, over the multiple layers, one or more additional layers including a metal layer, the back metal structure being formed by the multiple layers and the additional layers. A photovoltaic device is also described that includes a back metal structure disposed over a back surface of a photovoltaic structure made of a group III-V semiconductor material, the back metal structure including one or more evaporated layers disposed over multiple sputtered layers, the one or more evaporated layers including a metal layer. By allowing evaporation along with sputtering, tool size and costs can be reduced, including minimizing a number of vacuum breaks. Moreover, good yield and reliability, such as reducing dark line defects (DLDs), can also be achieved.

An assembly for optical to electrical power conversion including a photodiode assembly having a substrate layer and an internal side, an antireflective layer, a heterojunction buffer layer adjacent the internal side; an active area positioned adjacent the heterojunction buffer layer, a plurality of n+ electrode regions and p+ electrode regions positioned adjacent the active area, and back-contacts configured to align with the n+ and p+ electrode regions. The active area converts photons from incoming light into liberated electron hole pairs. The heterojunction buffer layer prevents electrons and holes of the liberated electron hole pairs from moving toward the substrate layer. The plurality of electrode regions are configured in an alternating pattern with gaps between each n+ and p+ electrode region. The electrode regions receive and generate electrical current from migration of the electrons and the holes, provide electrical pathways for the electrical current, and provide thermal pathways to dissipate heat.