High efficiency solar cells utilizing wafer bonding and layer transfer to integrate non-lattice matched materials

A multi-junction solar cell device comprising:

• a handle substrate;
• a plurality of cells comprising:
• an InGaAs cell bonded to the handle substrate, and at least one of:
• an InP cell;
• and an InGaAsP cell, wherein a wafer-bonded tunnel junction is formed between adjacent ones of said plurality of cells;
• a first contact tab electrically connected to a first one of said plurality of cells and a second contact tab electrically connected to a second one of said plurality of cells;
• a contact layer deposited on said plurality of cells, wherein a protruding section of said contact layer forms a first offset region, said first offset region including one of the first contact tab and the second contact tab;
• an insulating spacer layer deposited on the contact layer, said insulating spacer layer comprising a material selected to have a refractive index and thermal expansion coefficient closely matching a cell contacting the contact layer;
• a plurality of second cells selected from a group consisting of:
• a first group comprising an InGaP cell on a GaAsP cell, and a second group comprising an AlInP cell on InGaP cell, and
• a conductive layer, including a second offset region protruding from a stack formed from said plurality of second cells, said conductive layer positioned between the plurality of second cells and the insulating spacer layer, said second offset region incorporating a second grouping contact tab electrically connected to the plurality of second cells.

A multi-junction solar cell device comprising:

• a handle substrate;
• a cell grouping comprising:
• an InGaAs cell formed on a donor film and wafer-bonded to the handle substrate;
• and
• at least one of:
• an InP cell, and an InGaAsP cell, wherein a wafer-bonded tunnel junction is formed between adjacent ones of the cells in the cell grouping;
• and
• a first tab electrically connected to a topmost cell of said cell grouping and a second tab electrically connected to the InGaAs cell;
• an electrically conductive layer deposited on the most cell of the cell grouping, said electrically conductive layer forming an offset region protruding from the cell grouping, wherein the first tab is formed on the offset region;
• an insulating spacer layer formed on said electrically conductive layer, said insulating spacer layer comprising a material selected to have a refractive index and thermal expansion coefficient that closely matches the topmost cell of said cell grouping;
• a second conductive layer formed on the insulating spacer layer, said second conductive layer comprising a second offset region;
• a second cell grouping formed on said second conductive layer, other than said second offset region, said second cell grouping selected from a group consisting of:
• a first group comprising an InGaP cell on a GaAsP cell, and a second group comprising an AlInP cell on an InGaP cell, said second offset region, extending from the second cell grouping, comprising a second cell grouping contact tab electrically connected to the second cell grouping.

A multi-junction solar cell device comprising:

• a handle substrate;
• a first cell group comprising an InGaAs cell, grown on a donor film, and a cell selected from a group consisting of:
• an InP cell, and an InGaAsP cell, wherein the InGaAs cell is layer transferred to the handle substrate,
• a first contact tab electrically connected to the cell selected from the group consisting of:
• the InP cell and the InGaAsP cell, and a second contact tab electrically connected to said InGaAs cell;
• an electrically conductive layer comprising an offset region protruding from the cell selected from the group consisting of:
• the InP cell and the InGaAsP cell, said electrically conductive offset region containing the first contact tab;
• an insulating spacer layer formed on the electrically conductive layer, said insulating spacer layer comprising a material selected to have a refractive index and thermal expansion coefficient closely matching the cell selected from the group consisting of:
• the InP cell and the InGaAsP cell adjacent to said electrically conductive layer;
• a second cell group selected from a group consisting of:
• an InGaP cell on a GaAsP cell, and an AlInP cell on an InGaP cell, and
• a second conductive layer formed on a surface of the insulating spacer layer wherein the second cell group is positioned on the second conductive layer, said second conductive layer including a second offset region protruding from the second cell group, said second offset region incorporating thereon, a second group contact tab electrically connected to the second cell group.

A solar cell comprising:

• a first cell comprising;
• an InGaAs cell and at least one of:
• an InGaAsP and an InP cell, wherein the InGaAs cell being formed on the handle substrate;
• a separation layer, deposited on the first cell, comprising:
• a first metal layer formed on the first cell, a section of the first metal layer extending beyond said first cell, said extended section of the first metal layer forming a first offset region;
• an insulating spacer layer deposited on the first metal layer, said insulating spacer layer comprising a material selected to have a refractive index and thermal expansion coefficient closely matching a cell of said first cell adjacent to said first metal layer;
• and
• a second metal layer formed on a side of the insulating spacer layer opposite a side of the insulating spacer layer the first metal layer is located on, a section of said second metal layer extending beyond said second cell, said extended section of said second metal layer forming a second offset region;
• and
• a second cell, formed on the second metal layer, comprising:
• a second cell group selected from a group consisting of:
• an InGaP cell on a GaAsP cell and an AlInP cell on an InGaP cell, wherein
• a first cell contact is formed on the first offset region;
• and
• a second cell contact is formed on the second offset region.