HIGH TEMPERATURE SURVIVABLE INDIUM PHOSPHIDE SOLAR CELLS

HIGH TEMPERATURE (>600 DEGREES CELSIUS) INDIUM PHOSPHIDE (INP) SPACE SOLAR CELLS ARE BEING DEVELOPED TO ELIMINATE THEPROBLEMS, SURFACE DECOMPOSITION AND CONTACT FAILURE, ENCOUNTERED WHEN INP SOLAR CELLS ARE EXPOSED TO HIGH TEMPERATURES. KEY TO THIS PROGRAM ARE THE USE OF AN ENCAPSULANT LAYER TO ARREST SURFACE DECOMPOSITION AND A HIGHLY-STABLE INTERMEDIATE DEGENERATE SEMICONDUCTOR CONTACT SYSTEM DESIGNED TO ELIMINATE CONTACT FAILURE AT HIGH TEMPERATURES. THIS METHOD IS SUPERIOR TO OTHER INP HIGH TEMPERATURE APPROACHES BECAUSE IT COMBINES EXISTING EXPERIENCE IN THE THREE TECHNICAL AREAS: PROPRIETARY ENCAPSULANT, INTERMEDIATE SEMICONDUCTOR LAYER (ISL) CONTACTS, AND A PRECISE INP SOLAR CELL MODEL. STABLE ENCAPSULATION OF INP AT 600 DEGREES CELSIUS HAS ALREADY BEEN DEMONSTRATED, AND HIGH TEMPERATURE CONTACTS TO GAAS AT 600 DEGREES CELSIUS HAS BEEN ACHIEVED USING THE INTERMEDIATE SEMICONDUCTOR LAYER APPROACH. WITH A SUITABLE SURFACE ENCAPSULANT, THE INTERMEDIATE SEMICONDUCTORLAYER APPROACH IS EXPECTED TO LEAD TO THE BEST HIGH TEMPERATURE PERFORMANCE BECAUSE IT USES A BASE METAL LAYER WHICH FORMS A SEMICONDUCTOR RATHER THAN ALLOYING WITH THE INP. THIS PROGRAM IS EXPECTED TO RESULT IN 600 DEGREES CELSIUS SURVIVABLE INP SPACE SOLAR CELLS. HIGH TEMPERATURE PROTOTYPE INP SOLAR CELL HARDWARE ARE BEING DEMONSTRATED IN THIS PROGRAM. THE 600 DEGREES CELSIUS SURVIVABLE INP SOLAR CELL WOULD MAKE POSSIBLE NEW, HIGHER CONCENTRATION SOLAR CONCENTRATION DESIGNS FOR BOTH SPACE ANDTERRESTRIAL USE. THE NATURAL RADIATION RESISTANCE OF INP WOULD MAKE THIS TECHNOLOGY THE MOST SURVIVABLE FOR SPACE POWER APPLICATION. IN ADDITION TO PHOTOVOLTAIC USE, THE ENCAPSULANT-ISL CONTACT SYSTEM WOULD HAVE BROAD APPLICATION TO OTHER INP-BASED OPTOELECTRONIC DEVICES, INCLUDING INGAASP QUATERNARY DEVICES, LEADING TO IMPROVED SURVIVABILITY FOR THESE STRATEGIC DEVICES.