Abstract: A photovoltaic device, particularly a solar cell, comprises an interface between a layer of Group III-V material and a layer of Group IV material with a thin silicon diffusion barrier provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells.

Abstract: A photovoltaic device, particularly a solar cell, comprises an interface between a layer of Group III-V material and a layer of Group IV material with a thin silicon diffusion barrier provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells.

Abstract: There is disclosed a method of forming layers of either GaAs or germanium materials such as SiGe. The germanium material, for example, may be epitaxially grown on a GaAs surface. Layer transfer is used to transfer the germanium material, along with some residual GaAs, to a receiver substrate. The residual GaAs may be then removed by selective etching, with the boundary between the GaAs and the germanium material providing an etch stop.

Abstract: A photovoltaic device comprises an interface (8) between a layer of Group III-V material (3) and a layer of Group IV material (1) with a thin silicon diffusion barrier (6) provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells. In another aspect, a multijunction photovoltaic device is provided in which there are at least a first light-absorbing layer (111) of SiGe or SiGeSn and a second light-absorbing layer (112) of SiGeSn, both layers being lattice-matched to GaAs.

Abstract: There is disclosed a photovoltaic cell, such as a solar cell, incorporating one or more epitaxially grown layers of SiGe or another germanium material, substantially lattice matched to GaAs. A GaAs substrate used for growing the layers may be removed by a method which includes using a boundary between said GaAs and the germanium material as an etch stop.

Abstract: There is disclosed a method of forming layers of either GaAs or germanium materials such as SiGe. The germanium material, for example, may be epitaxially grown on a GaAs surface. Layer transfer is used to transfer the germanium material, along with some residual GaAs, to a receiver substrate. The residual GaAs may be then removed by selective etching, with the boundary between the GaAs and the germanium material providing an etch stop.