Device structures, apparatuses, and methods are disclosed for photovoltaic cells that may be a single junction or multijunction solar cells, with at least one layer comprising a group-IV semiconductor in which part of the cell comprises a second layer comprising a III-V semiconductor or group-IV semiconductor having a different composition than the group-IV semiconductor of the first layer, such that a heterostructure is formed between the first and second layers.

Device structures, apparatuses, and methods are disclosed for photovoltaic cells that may be a single junction or multijunction solar cells, with at least one layer comprising a group-IV semiconductor in which part of the cell comprises a second layer comprising a III-V semiconductor or group-IV semiconductor having a different composition than the group-IV semiconductor of the first layer, such that a heterostructure is formed between the first and second layers.

A backside illuminated multi-junction solar cell module includes a substrate, multiple multi-junction solar cells, and a cell interconnection that provides a series connection between at least two of the multi-junction solar cells. The substrate may include a material that is substantially transparent to solar radiation. Each multi-junction solar cell includes a first active cell, grown over the substrate, for absorbing a first portion of the solar radiation for conversion into electrical energy and a second active cell, grown over the first active cell, for absorbing a second portion of the solar radiation for conversion into electrical energy. At least one of the first and second active cells includes a nitride.

A backside illuminated multi-junction solar cell module includes a substrate, multiple multi-junction solar cells, and a cell interconnection that provides a series connection between at least two of the multi-junction solar cells. The substrate may include a material that is substantially transparent to solar radiation. Each multi-junction solar cell includes a first active cell, grown over the substrate, for absorbing a first portion of the solar radiation for conversion into electrical energy and a second active cell, grown over the first active cell, for absorbing a second portion of the solar radiation for conversion into electrical energy. At least one of the first and second active cells includes a nitride.

A multijunction solar cell in accordance with an example implementation includes a growth substrate; a first solar subcell disposed over or in the growth substrate; a tunnel diode disposed over the first solar subcell; and a grading interlayer directly disposed over the tunnel diode; a sequence of layers of semiconductor material forming a solar cell disposed over the grading interlayer comprising a plurality of solar subcells. The multijunction solar cell also includes a first wafer bowing inhibition layer disposed directly over an uppermost sublayer of the grading interlayer, such bowing inhibition layer having an in-plane lattice constant greater than the in-plane lattice constant of the uppermost sublayer of the grading interlayer. A second wafer bowing inhibition layer is disposed directly over the first wafer bowing inhibition layer.

A multijunction solar cell including an upper first solar subcell; a second solar subcell adjacent to the first solar subcell; a first graded interlayer adjacent to the second solar subcell; a third solar subcell adjacent to the first graded interlayer such that the third subcell is lattice mismatched with respect to the second subcell. A second graded interlayer is provided adjacent to the third solar subcell, and a lower fourth solar subcell is provided adjacent to the second graded interlayer, such that the fourth subcell is lattice mismatched with respect to the third subcell. An encapsulating layer composed of silicon nitride or titanium oxide disposed on the top surface of the solar cell, and an antireflection coating layer disposed over the encapsulating layer.

A solar cell stack includes a first semiconductor solar cell having a p-n junction made of a first material with a first lattice constant, a second semiconductor solar cell having a p-n junction made of a second material with a second lattice constant, and the first lattice constant being at least 0.008 Å smaller than the second lattice constant, and a metamorphic buffer. The metamorphic buffer is formed between the first semiconductor solar cell and the second semiconductor solar cell. The metamorphic buffer includes a series of at least five layers. The lattice constant increases in the series in the direction of the semiconductor solar cell. The lattice constants of the layers of the metamorphic buffer are larger than the first lattice constant. Two layers of the buffer having a doping and the difference in the dopant concentration between the two layers being greater than 4E.sup.17 cm.sup.−3.

A solar cell stack includes a first semiconductor solar cell having a p-n junction made of a first material with a first lattice constant, a second semiconductor solar cell having a p-n junction made of a second material with a second lattice constant, and the first lattice constant being at least 0.008 Å smaller than the second lattice constant, and a metamorphic buffer. The metamorphic buffer is formed between the first semiconductor solar cell and the second semiconductor solar cell. The metamorphic buffer includes a series of at least five layers. The lattice constant increases in the series in the direction of the semiconductor solar cell. The lattice constants of the layers of the metamorphic buffer are larger than the first lattice constant. Two layers of the buffer having a doping and the difference in the dopant concentration between the two layers being greater than 4E.sup.17 cm.sup.−3.

High efficiency dilute nitride bismide alloys and multijunction photovoltaic cells incorporating the high efficiency dilute nitride bismide alloys are disclosed. Bismuth-containing dilute nitride subcells exhibit a high efficiency across a broad range of irradiance energies, a high short circuit current density, and a high open circuit voltage.

High efficiency dilute nitride bismide alloys and multijunction photovoltaic cells incorporating the high efficiency dilute nitride bismide alloys are disclosed. Bismuth-containing dilute nitride subcells exhibit a high efficiency across a broad range of irradiance energies, a high short circuit current density, and a high open circuit voltage.