US 12,080,820 B2
Group-IV solar cell structure using group-IV heterostructures
Richard R. King, Thousand Oaks, CA (US); Christopher M. Fetzer, Sylmar, CA (US); and Nasser H. Karam, La Canada, CA (US)
Assigned to THE BOEING COMPANY, Arlington, VA (US)
Filed by The Boeing Company, Chicago, IL (US)
Filed on Mar. 28, 2022, as Appl. No. 17/656,661.
Application 17/656,661 is a continuation of application No. 17/074,272, filed on Oct. 19, 2020.
Application 17/074,272 is a continuation of application No. 15/908,442, filed on Feb. 28, 2018, granted, now 10,811,553, issued on Oct. 20, 2020.
Application 15/908,442 is a continuation of application No. 14/807,347, filed on Jul. 23, 2015, granted, now 9,947,823, issued on Apr. 17, 2018.
Application 14/807,347 is a continuation of application No. 13/617,886, filed on Sep. 14, 2012, granted, now 9,099,595, issued on Aug. 4, 2015.
Prior Publication US 2022/0216358 A1, Jul. 7, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 31/074 (2012.01); H01L 31/0687 (2012.01); H01L 31/0725 (2012.01); H01L 31/0735 (2012.01); H01L 31/0745 (2012.01); H01L 31/078 (2012.01); H01L 31/18 (2006.01)
CPC H01L 31/074 (2013.01) [H01L 31/0687 (2013.01); H01L 31/0725 (2013.01); H01L 31/0735 (2013.01); H01L 31/0745 (2013.01); H01L 31/078 (2013.01); H01L 31/18 (2013.01); Y02E 10/50 (2013.01); Y02E 10/544 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A photovoltaic cell comprising:
a plurality of III-V subcells;
a first group-IV subcell comprising:
an n-type emitter layer comprising a first group-IV material selected from a first group consisting of: Ge, SiGe and SiGeSn; and
a second layer chosen from a p-type group-IV semiconductor base layer or a p-type group-IV semiconductor back-surface field (BSF) layer, the second layer comprising a second group-IV material, said second group-IV material being different from the first group-IV material, and the n-type emitter layer being the primary photoabsorber of the first group-IV subcell;
wherein a p-n junction of the first group-IV subcell is formed at a heterojunction of the n-type emitter layer and second layer, and
wherein the n-type emitter layer is thicker than the second layer;
a group III-V nucleation layer situated between the plurality of III-V subcells and the first group-IV subcell;
a group IV window layer situated between the n-type emitter layer and the group III-V nucleation layer, wherein the group IV window layer is in direct contact with the n-type emitter layer and the group III-V nucleation layer;
a tunnel junction; and
a second group-IV subcell, the tunnel junction interconnecting the first group IV subcell to the second group-IV subcell, the first group IV subcell and the second group IV subcell being a lowest two subcells of the photovoltaic cell, the first group IV subcell being between the second group-IV subcell and the plurality of III-V subcells.