An intermediate substrate includes a handle substrate bonded to a thin layer suitable for epitaxial growth of a compound semiconductor layer, such as a III-nitride semiconductor layer. The handle substrate may be a metal or metal alloy substrate, such as a molybdenum or molybdenum alloy substrate, while the thin layer may be a sapphire layer. A method of making the intermediate substrate includes forming a weak interface in the source substrate, bonding the source substrate to the handle substrate, and exfoliating the thin layer from the source substrate such that the thin layer remains bonded to the handle substrate.

Bonded intermediate substrate and method of making same

In one embodiment, a method of forming a multijunction solar cell having lattice mismatched layers and lattice-matched layers comprises growing a top subcell having a first band gap over a growth semiconductor substrate. A middle subcell having a second band gap is grown over the top subcell, and a lower subcell having a third band gap is grown over the middle subcell. The lower subcell is substantially lattice-mismatched with respect to the growth semiconductor substrate. The first band gap of the top subcell is larger than the second band gap of the middle subcell. The second band gap of the middle subcell is larger than the third band gap of the lower subcell. A support substrate is formed over the lower subcell, and the growth semiconductor substrate is removed. In various embodiments, the multijunction solar cell may further comprise additional lower subcells. A parting layer may also be provided between the growth substrate and the top subcell in certain embodiments. Embodiments of this reverse process permit the top and middle subcells to have high performance by having atomic lattice spacing closely matched to that of the growth substrate. Lower subcells can be included with appropriate band gap, but with lattice spacing mismatched to the other subcells. The reduced performance caused by strain resulting from mismatch can be mitigated without reducing the performance of the upper subcells.

High efficiency, monolithic multijunction solar cells containing lattice-mismatched materials and methods of forming same

A multi-junction solar cell includes a silicon solar subcell, a GaInP solar subcell, and a GaAs solar subcell located between the silicon solar subcell and the GaInP solar subcell. The GaAs solar subcell is bonded to the silicon solar subcell such that a bonded interface exists between these subcells.

GaInP/GaAs/Si TRIPLE JUNCTION SOLAR CELL ENABLED BY WAFER BONDING AND LAYER TRANSFER

A solar cell comprising a substrate, a buffer layer, a first subcell, a second subcell, and a third subcell, where said first subcell, said second subcell, and said third subcell are lattice matched, and where said substrate is lattice mismatched with said first, second, and third subcells.

Multi-junction photovoltaic cell

A multi-junction solar cell includes an active silicon subcell, a first non-silicon subcell bonded to a first side of the active silicon subcell, and a second non-silicon subcell bonded to a second side of the active silicon subcell. This and other solar cells may be formed by bonding and layer transfer.

Multi-junction solar cells and methods of making same using layer transfer and bonding techniques

A photoelectric converting device is provided with enhanced photoelectric conversion efficiency by optimizing a combination of materials used for top and bottom cells. The photoelectric converting device of the present invention is provided with first and second pn junctions. The first pn junction is formed in a semiconductor substantially represented by (Al 1−y Ga y ) 1−x In x P, and the second pn junction is formed in a semiconductor substantially represented by Ga 1−z In z As.

Yuji Komatsu

Papers

Photoelectric converting device