A monolithic multiple solar cell includes at least three partial cells, with a semiconductor mirror placed between two partial cells. The aim of the invention is to improve the radiation stability of said solar cell. For this purpose, the semiconductor mirror has a high degree of reflection in at least one part of a spectral absorption area of the partial cell which is arranged above the semiconductor mirror and a high degree of transmission within the spectral absorption range of the partial cell arranged below the semiconductor mirror.

A compound photovoltaic cell includes a substrate, a first cell made of a first semiconductor material and formed on the substrate, a tunnel layer, and a second cell made of a second semiconductor material lattice mismatched with a material of the substrate, connected to the first cell via the tunnel layer, and disposed on an incident side with respect to the first cell, wherein band gaps of the first and the second cells become smaller from an incident side to a back side, and wherein the tunnel layer includes a p-type layer disposed on the incident side and a n-type layer disposed on the back side, the p-type layer being a p.sup.+-type (Al)GaInAs layer, the n-type layer being an n.sup.+-type InP layer, an n.sup.+-type GaInP layer having a tensile strain with respect to InP or n.sup.+-type Ga(In)PSb layer having a tensile strain with respect to InP.

Embodiments of the invention generally relate to photovoltaic devices. In one embodiment, a method for forming a gallium arsenide based photovoltaic device includes providing a semiconductor structure, the structure including an absorber layer comprising gallium arsenide. A bypass function is provided in a p-n junction of the semiconductor structure, where under reverse-bias conditions the p-n junction breaks down in a controlled manner by a Zener breakdown effect.

A photoelectric conversion element includes a photoelectric conversion layer having the quantum structure and utilizes intersubband transition in a conduction band. The photoelectric conversion element includes a superlattice semiconductor layer in which a barrier layer and a quantum dot layer as a quantum layer are alternately and repeatedly stacked. The barrier layer includes an indirect transition semiconductor material, and the quantum dot layer has a nano-structure including a direct transition semiconductor material. The indirect transition semiconductor material constituting the barrier layer has a bandgap of more than 1.42 eV at room temperature.

Optoelectric devices that comprise a semiconductor superlattice heterostructure. One or more individual layers within the semiconductor superlattice heterostructure can further comprise layers of differing thicknesses. In at least one embodiment, an optoelectric device with specially engineered layers can generate an output wavelength of between 3 m to 15 m at output power levels of 0.01 mW to 100 mW.

An nitride semiconductor device for the improvement of lower operational voltage or increased emitting output, comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride. semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1xN (0<x<1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn in a range of 510.sup.16 to 210.sup.18/cm.sup.3.

A stacked multi-junction solar cell having a first subcell and second subcell, the second subcell having a larger band gap than the first subcell. A third subcell has a larger band gap than the second subcell, and each of the subcells include an emitter and a base. The second subcell has a layer which includes a compound formed at least the elements GaInAsP, and a thickness of the layer is greater than 100 nm, and the layer is formed as part of the emitter and/or as part of the base and/or as part of the space-charge zone situated between the emitter and the base. The third subcell has a layer including a compound formed of at least the elements GaInP, and the thickness of the layer is greater than 100 nm.

A solar cell including a sequence of layers of semiconductor material forming a solar cell; a metal contact layer over said sequence of layers; a permanent supporting substrate composed of a carbon fiber reinforced polymer utilizing a conductive polyimide binding resin disposed directly over said metal contact layer and permanently bonding thereto.

Photovoltaic devices including direct gap III-V absorber materials and operatively associated back structures enhance efficiency by enabling photon recycling. The back structures of the photovoltaic devices include wide bandgap III-V layers, highly doped (In)GaAs layers, patterned oxide layers and metal reflectors that directly contact the highly doped (In)GaAs layers through vias formed in the back structures. Localized ohmic contacts are formed in the back structures of the devices.

The disclosure describes multi-junction solar cell structures that include two or more graded interlayers.