ALUMINUM-GALLIUM-ARSENIDE TOP SOLAR CELL FOR MECHANICAL ATTACHMENT TO A SILICON CONCENTRATOR WITH IMPROVED AMO EFFICIENCY

INCREASES IN SOLAR CELL EFFICIENCY CAN BE ACHIEVED WITH TANDEM MULTI-JUNCTION STRUCTURES TO IMPROVE THE PERFORMANCE AND SCALE OF SPACE PHOTOVOLTAIC CONCENTRATORS. THE "TOP SOLAR CELL" TANDEM APPROACH COULD INCREASE ENERGY CONVERSION EFFICIENCY BY AS MUCH AS 100%. A SELF-SUPPORTING ALUMINUM-GALLIUM-ARSENIDE (ALGAAS) TOP SOLAR CELL IS BEING DEVELOPED FOR MECHANICAL ATTACHMENT TO A SILICON CONCENTRATOR SOLAR CELL. A L.93EV ALGAAS COMPOSITION IS BEING INVESTIGATED FOR A FOUR-THERMAL WIRING CONFIGURATION, WHILE A 1.76 EV ALGAAS COMPOSITION IS BEING CONSIDERED FOR A TWO-TERMINAL CONFIGURATION. TO AVOID MATERIAL RELATED PROBLEMS, LIQUID PHASE EPITAXY IS BEING USED. THE TWO DIFFERENT DESIGN STRUCTURES TAKE ADVANTAGE OF EXISTING LIGHT EMITTING DIODE TECHNOLOGIES. PRACTICAL EFFICIENCIES IN EXCESS OF 30% AMO ARE EXPECTED UNDER 100X CONCENTRATION. TWO AND FOUR-TERMINAL ALGAAS/SI MECHANICALLY STACKED PROTOTYPES ARE EXPECTED TO BE FABRICATED AT THE END OF THE RESEARCH EFFORT. ALTHOUGH PROPOSED FOR A CONCENTRATOR SYSTEM, THE ALGAAS TOP SOLAR CELL IS EASILY ADAPTABLE TO A FLAT PANEL ARRAY. WHEN SUCCESSFUL, THIS APPROACH WILL HAVE A LARGE NUMBER OF HIGH PERFORMANCE OF SPACE AND TERRESTIAL POWER APPLICATIONS.