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Space Products: Cells and Cics

Spectrolab produces multijunction GaInP2/GaAs/Ge solar cells for space applications.  Our most recent products are three junction solar cells in which each sub-cell reacts to a different portion of the incident solar spectrum to maximize response, and then operate collectively in series to provide an overall efficiency of 26-31% (Beginning of Life) depending on the product.  These solar cells are tuned to optimize performance at End of Life by harmonizing each cell’s current output after exposure to a typical 15 year mission in geosynchronous orbit.

Spectrolab grows the solar cell’s individual layers onto germanium substrates via a process called Metal Organic Vapor Phase Epitaxy.  Metallization is applied to both front and rear sides of the solar cells.  Anti-reflection coatings are also applied to maximize use of incident light. Once this processing is completed, individual cells are cut from the germanium wafer with a diamond embedded saw.

After solar cells are tested they are either shipped to customers or forwarded internally for assembly into CICs (Cells-Interconnects-Coverglass and bypass diode).  Space-qualified coverglass is applied to the front of the solar cell with a transparent adhesive to capture high energy electrons that would otherwise damage the solar cell and limit performance in space.  Interconnects for routing power out of the cell are welded onto the front and back of the cell.  A bypass diode that protects the cell when solar cell circuits become partially shadowed and drive the shadowed cells into reverse bias.

All solar cells inspected for mechanical defects and electrically tested.  All solar cell products have completed extensive qualification testing for Leo and Geo environments.

Spectrolab utilizes state of the art semiconductor process control tools, such as Six Sigma and DoE, to minimize process variability and maximize product quality for flawless operation in the extreme space environment.


Data Sheets (pdf)

30.7% NeXt Triple Junction (XTJ) Prime Solar Cells
29.5% NeXt Triple Junction (XTJ) Solar Cells
28.3% Ultra Triple Junction (UTJ) Solar Cells
26.8% Improved Triple Junction (ITJ) Solar Cells