Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

Technical Report · Tue Jul 31 00:00:00 EDT 2012

DOI:https://doi.org/10.2172/1146980· OSTI ID:1146980

Bedair, Salah M. ^[1]; Hauser, John R. ^[1]; Elmasry, Nadia ^[1]; Colter, Peter C. ^[1]; Bradshaw, G. ^[1]; Carlin, C. Z. ^[1]; Samberg, J. ^[1]; Edmonson, Kenneth ^[2]

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1. North Carolina State Univ., Raleigh, NC (United States)
2. Spectrolab, Inc., Sylmar, CA (United States)

We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the In_xGa_1-xAs/GaAs_1-yP_y SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

• Research Organization: North Carolina State Univ., Raleigh, NC (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• Contributing Organization: Spectrolab, Inc., Sylmar, CA (United States)
• DOE Contract Number: FG36-08GO18072
• OSTI ID: 1146980
• Report Number(s): DOENCSU-18072
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
Multjunction
Quantum well