Development of Lattice-Mismatched GaInAsP for Radiation Hardness

Journal Article · Wed Jan 01 04:00:00 EST 2020 · IEEE Journal of Photovoltaics

DOI:https://doi.org/10.1109/JPHOTOV.2019.2947555· OSTI ID:1592086

France, Ryan M. ^[1]; Espinet-Gonzalez, Pilar ^[2]; Haidet, Brian B. ^[3]; Mukherjee, Kunal ^[3]; Guthrey, Harvey L. ^[1]; Atwater, Harry A. ^[2]; Walker, Don ^[4]

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1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
2. California Inst. of Technology (CalTech), Pasadena, CA (United States)
3. Univ. of California, Santa Barbara, CA (United States)
4. Aerospace Corporation, El Segundo, CA (United States)

We develop lattice-mismatched GaInAsP as an alternative alloy to pure As-based alloys currently used in III-V multijunction solar cells. Increasing the alloy phosphorous and indium content while maintaining an optimal bandgap may allow high efficiency multijunction devices with increased radiation hardness. Here, 1.0-eV GaInAsP is developed and implemented into single and multijunction solar cell devices. The lattice-mismatched GaInAsP must be grown strain free, and the subcell thickness must be maintained below the thickness where surface-driven phase separation occurs. As observed in transmission electron microscopy and cathodoluminescence imaging, phase separation strengthens in the GaInAsP layer and leads to interfacial defect formation when the cell thickness is too great. We show single junction 1.0-eV Ga 0.5 In 0.5 As 0.7 P 0.3 with excellent carrier collection and a bandgap-voltage offset of 0.40 V. This material quality approaches that of 1.0-eV Ga 0.7 In 0.3 As used in inverted metamorphic multijunction devices, but has increased phosphorus content and consequently is expected to have a higher radiation resistance. We incorporate the 1.0-eV GaInAsP subcell into a 3-junction inverted metamorphic solar cell to test the performance of the subcell in a multijunction. No additional loss is observed upon integration into a multijunction cell: both the carrier collection and voltage of the GaInAsP subcell are unchanged from single junction devices. While further materials development and radiation testing is still required, these preliminary results indicate that lattice-mismatched GaInAsP can be effectively used in multijunction solar cells to replace radiation-soft materials.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE); Northrop Grumman; Aerospace Corporation; National Science Foundation (NSF)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1592086
• Report Number(s): NREL/JA--5900-74068
• Journal Information: IEEE Journal of Photovoltaics, Journal Name: IEEE Journal of Photovoltaics Journal Issue: 1 Vol. 10; ISSN 2156-3381
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
III-V semiconductor materials
gallium arsenide
photovoltaic cells
radiation hardening