Flight Demonstration of IMM3J Space Solar Cell Film in Space

The output parameters of InGaP/GaAs/InGaAs inverted metamorphic triple-junction (IMM3J) space solar cells have been collected for about 3.5 years in orbit. The cells are mounted on “HISAKI” (SPRINT-A) small scientific satellite which was launched on September 14th, 2013. We developed a component to demonstrate next-generation instruments for electrical power systems, and we named it NESSIE (Next-generation Small Satellite Instruments for Electrical Power System). The degradation trends of the IMM3J cells on NESSIE confirmed that the conventional RDC method can be applied to degradation prediction of IMM3J cells which have thin-film structure. To the best of our knowledge, this is the first flight demonstration of IMM3J cells in the world.27th International Photovoltaic Science and Engineering Conference (PVSEC-27

Improved crystallinity of GaP-based dilute nitride alloys by proton/electron irradiation and rapid thermal annealing

This study presents the positive effects of proton/electron irradiation on the crystallinity of GaP-based dilute nitride alloys. It is found that proton/electron irradiation followed by rapid thermal annealing enhances the PL peak intensity of GaPN alloys, whereas major photovoltaic III–V materials such as GaAs and InGaP generally degrade their crystal quality by irradiation damage. Atomic force microscopy and transmission electron microscopy reveal no degradation of structural defects. GaAsPN solar cell test devices are then fabricated. Results show that the conversion efficiency increases by proton/electron irradiation, which is mainly caused by an increase in the short-circuit current