Solar cell device

A solar cell device comprising:

• a multi-junction solar cell;
• and
• a protection diode structure,
• wherein the multi-junction solar cell and the protection diode structure have a common rear surface and the multi-junction solar cell and the protection diode structure each having front sides separated by a mesa trench,
• wherein the common rear surface comprises an electrically conductive layer extending along a full length of the common rear surface under the multi-junction solar cell and the protection diode structure, and light enters through the front side of the multi-junction solar cell,
• wherein, the multi-junction solar cell comprises a stack of at least three solar cells including a top solar cell placed closest to the front side of the multi-junction solar cell and a bottom solar cell placed closest to the common rear surface, and each of the at least three solar cells comprises an n-p junction, and a solar cell tunnel diode is placed between adjacent solar cells,
• wherein a number of semiconductor layers in the protection diode structure is smaller than a number of semiconductor layers in the multi-junction solar cell, the multi-junction solar cell including additional semiconductor layers,
• wherein a sequence of the semiconductor layers in the protection diode structure is identical to a sequence of remaining semiconductor layers of the multi-junction solar cell without the additional semiconductor layers,
• wherein at least one top protection diode adjacent to the front side of the protection diode structure and a bottom protection diode placed closest to the common rear surface are provided and a protection diode tunnel diode is placed between adjacent protection diodes,
• wherein the protection diode structure comprises at least two n-p junctions,
• wherein a number of the n-p junctions in the protection diode structure is smaller at least by one than a number of the n-p junctions of the multi-junction solar cell,
• wherein a protection diode terminal contact structure containing one or more metal layers is formed on the front side of the protection diode structure and a first electrically conductive contact layer is formed directly below the protection diode terminal contact structure, the first electrically conductive contact layer having a plurality of contact layer semiconductor layers including a first additional tunnel diode, and
• wherein a solar cell terminal contact structure containing one or more metal layers is formed on the front side of the multi-junction solar cell and a second electrically conductive contact layer is formed directly below the solar cell terminal contact structure, the second electrically conductive contact layer having a plurality of contact layer semiconductor layers including a second additional tunnel diode, and,
• wherein the electrically conductive layer is a rear terminal contact disposed along the common rear surface beneath the multi-junction solar cell and the protection diode structure, the rear terminal contact comprising a top layer of Au and Ge, a bottom layer of Au, and a layer of Ag disposed between the top layer and the bottom layer.