Solar Junction Announces Development Plans for 4J Space Cell Product

Solar Junction announced an ambitious plan to become the leading provider of solar cells for space power applications. The company claims to offer the highest efficiency commercially available multi-junction solar cell for terrestrial concentrated photovoltaic (CPV) applications. Solar Junction says it is rapidly developing a fully lattice-matched, four-junction (4J) space cell product.

According to Solar Junction, its proprietary dilute nitride technology platform enables the new 4J space cell product.  The company predicts air mass zero (AM0) efficiencies exceeding 33% by 2016.  At the 2015 Space Power Workshop in Manhattan Beach, California (May 11-14), the company reported to the aerospace industry its progress in developing 4J space solar cells.

Solar Junction reports that it is currently fabricating high efficiency  three-junction (3J) space cells using its dilute nitride material as the bottom active junction on a GaAs substrate. In 2014, the company began shipping its commercial 3J space cell with AM0 efficiencies exceeding 31%. The 3J product is undergoing qualification.

During the 2015 Space Power Workshop, The Aerospace Corporation presented radiation degradation results from two Aerospace AeroCube picosats that have been orbiting the Earth since June 2014. The picosats carry Solar Junction 3J space cells, demonstrating that dilute nitride materials have radiation hardness comparable to conventional cells. By late 2016, Solar Junction plans to bring to market its 4J, lattice-matched, dilute nitride, Ge bottom junction space cell with a minimum average efficiency of 33%.

The company uses molecular beam epitaxy and dilute nitrides to produce high-volume on 6-inch wafers. With its fabrication process the company says it can produce industry leading manufacturing yields and significant cost savings. Solar Junction says its proprietary dilute nitride technology is lattice matched on both Ge and GaAs substrates, offering bandgaps ranging between 0.9 eV and 1.4 eV. The company boasts that its technology platform is the only one that enables low-cost monolithic growth beyond three junctions.