US 11,658,256 B2
Multijunction solar cells
Daniel Derkacs, Albuquerque, NM (US); John Hart, Albuquerque, NM (US); and Zachary Bittner, Albuquerque, NM (US)
Assigned to SolAero Technologies Corp., Albuquerque, NM (US)
Filed by SolAero Technologies Corp., Albuquerque, NM (US)
Filed on Dec. 7, 2020, as Appl. No. 17/114,158.
Claims priority of provisional application 62/948,451, filed on Dec. 16, 2019.
Prior Publication US 2021/0351313 A1, Nov. 11, 2021
Int. Cl. H01L 31/0725 (2012.01); H01L 31/18 (2006.01); H01L 31/0735 (2012.01)
CPC H01L 31/0725 (2013.01) [H01L 31/0735 (2013.01); H01L 31/1844 (2013.01); H01L 31/1892 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A multijunction space-qualified solar cell comprising:
an upper first solar subcell composed of indium gallium aluminum phosphide and having a first band gap in the range of 2.0 to 2.2 eV;
a second solar subcell adjacent to said first solar subcell and including an emitter layer composed of indium gallium phosphide or aluminum indium gallium arsenide, and a base layer composed of aluminum indium gallium arsenide and having a second band gap in the range of approximately 1.55 to 1.8 eV and being lattice matched with the upper first solar subcell, wherein the emitter and base layers of the second solar subcell form a photoelectric junction;
at least a third solar subcell adjacent to said second solar subcell and composed of indium gallium arsenide and having a third band gap less than that of the second solar subcell and being lattice matched with the second solar subcell; and
a bottom solar subcell disposed under said third solar subcell;
wherein at least a particular one of the subcells has a graded band gap throughout at least a portion of a thickness of its active layer, and wherein at least one of the following applies:
the band gap decreases from a top surface of the particular one of the subcells to a photoelectric junction of the particular one of the subcells; or
the band gap increases from the photoelectric junction of the particular one of the subcells to a bottom surface of the particular one of the subcells.